- Email: [email protected]
Reinforcement and processing on the machinability and mechanical properties of aluminum matrix composites
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
Available online at www.sciencedirect.com
www.jmrt.com.br
Original Article
Reinforcement and processing on the machinability and mechanical properties of aluminum matrix composites Fakhir Aziz Rasul Rozhbiany ∗ , Shawnim Rashied Jalal Department of Mechanical & Mechatronics Engineering, College of Engineering, Salahaddin University-Erbil, Erbil, Iraq
a r t i c l e
i n f o
a b s t r a c t
Article history:
Metal matrix composites are an essential product used in engineering materials. This prod-
Received 25 March 2019
uct has wide applications in automotive, aerospace, and other uses. In this paper, four
Accepted 16 August 2019
different reinforced such as (MA), (MCA), (NFC) and (SA) with a constant rate of 5 wt. %
Available online 30 August 2019
for each reinforced element used and mixed with Al 6063 alloy to produced composite by using modified two-step mechanical stirrer and having three blades at each step. Coated
Keywords:
carbide tool insert was carrying out the turning process. The chip volume ratio and chip
Mechanical properties
shape style formation were performed within cutting speeds of 10 and 90 m/min, which
Chip formation style
appears in different length and shapes especially at 90 m/min. The chip volume ratio is
Surface roughness
not increased by all four types of reinforced metal but still maintain in the standard range
Metal matrix composites (MMCs)
according to the shape of chips. NFC increasing average chip length during cutting speed of 10 m/min, but within cutting speed of 90 m/min, MA has an important role to change the volume and formation style of a chip from discontinuous chip to continuous chip. It should be noted from the results, that the NFC has decreased surface roughness dramatically for all cutting speeds and followed by MCA, but the MA and SA have less effect compared to NFC and MCA. The mechanical properties such as yield ultimate tensile strength and hardness of the composites are much more than Al 6063 alloy especially when adding all four types of reinforcement together moreover the effect of NFC is very less compared with other types of reinforced materials. MA increase hardness more than the different types of reinforcement. Microstructure observation produces compact grain boundaries with strong grains of metal matrix composites compared to Al 6063 alloys. © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
1.
∗
Introduction
Most of the researchers during the last three decades have been generated tremendous interested to use aluminum and its alloys due to their properties such as lightweight, excellent mechanical properties, low cost, good tribological properties,
Corresponding author. E-mail: [email protected] (F.A. Rozhbiany). https://doi.org/10.1016/j.jmrt.2019.08.023 2238-7854/© 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
Nomenclature Al MMCs MA NFC MCA SA SN Vc Ra La YTS UTS SEM R
Aluminum Metal matrix composites Mortar ash Nano fibrillated composite Met coke ash Straw ash Sample number Cutting speed Average surface roughness Average chip length Yield tensile strength Ultimate tensile strength Scanning electron microscope Chip volume ratio
good stiffness and best corrosion resistance compared to conventional metals [1–4]. So to perceived the improvement in the mechanical properties of Al alloy many additives were added and mixing with it to produced MMCs which consist of matrix and reinforcements. Composites are a unique class of materials invariably favored by nature in certain and humans from prehistoric times. Composites provide a unique capability of enhancing the selected properties of monolithic materials which remains superior to the monolithic counterparts. The enhancement in the targeted property of a metallic matrix can be controlled through the selection of types, size, volume fraction, orientation, microstructural parameters of the reinforcing materials, and the amount of reinforcement which forms the core of composite design in addition to the choice of matrix normally lightweight such as aluminum and magnesium and reinforcement such as nano-ceramic, nano oxides, carbon-based nano-allotropy, elements etc., the improvement in properties of MMCs crucially depends on the processing route and the processing parameters that can provide a uniform distribution of reinforcement and a good matrix-reinforcement interface [5,6]. Composites consist of metal matrix composites which have more characteristics such as better wear, fatigue, elastic properties, higher electric, and higher thermal conductivities and reinforced nanostructure which has low thermal conductivity and better shock resistance so composites give good combination of two or more materials to get best properties. Materials development has changed by shifting from monolithic to composite materials due to reduced weight, quality, high performance, and low cost. The design goal of composites is obtained by improved mechanical and functional properties [7–10]. Stir casting is a common, economical and relatively simple method to produce the MMCs called as materials system which has two or more micro/macro with different composition. Some properties of MMCs have better performance, high accuracy with a higher rate of production. An application of MMCs includes automotive area involves industrial applications because they have best properties. The homogeneous distributions of reinforcements in the matrix of processing
4767
MMCs are major challenges of production and it has a strong impact on the quality of properties and material [11–15].
2.
Literature review
Bodunrin et al. [16] developed many tested about agro wastes in MMCs include: bamboo leaf ash (BLA), rice husk ash (RHA), bagasse ash (BA), palm kernel shell ash (PKSA), maize stalk ash (MSA), corn cob ash (CCA), bean shell waste ash (BSWA) mentioned a few and the development of hybrid aluminum matrix composites (AMCs) with agro–waste ash serving as complementing reinforcement, agro waste has improvement for most properties of AMCs with single reinforced AMCs. Double synthetic reinforcement hybrid composites compared the mechanical properties obtain with unreinforced alloy rather than the single reinforced composite; therefore further investigation should be carried out to determine how much the mechanical properties are improved when comparing the hybrid composites with double synthetic reinforcement to single reinforced composites. Sood et al. [17] experimentally showed semi-solid metal processing carried out by mechanical stirring on the machinability studies of Al-20Si-0.5Mg-1.2Fe based alloy to determine the influence of cutting speed, feed rate and depth of cut by using the constant rate of beryllium and cadmium 0.03% as reinforced metal, the results show that the length of chip changed under different machining conditions, on the other hand, there is an improvement in the rate of surface roughness and cutting force. Hindi et al. [18] described ceramic material such as silicon carbide of 2, 4 and 6% as reinforcement are manufactured using conventional stir casting technique, the microstructure reveals better dispersion of reinforcement in the matrix, hardness and tensile strength of 6% SiC be higher than 2 & 4% but the ductility and the impact strength are improvements with 4% SiC. Phanibhubshana et al. [19] analyzed practically the application of varied rate of hematite also known as ferrous oxide (Fe2 O3 ) as reinforcement mixing with Al 6061 alloy by stir casting technique, hematite was added in different proportions 2, 4, 6 and 8, significant improvement in hardness and tensile strength were observed with the increase of hematite rate and microstructural studies showed better bonding and dispersion of the Fe2 O3 metal matrix composites. Alaneme et al. [20] investigated the combination of groundnut shell ash (GSA) and silicon carbide (SiC) with different mixing ratio (10:0, 7.5:2.5, 5.0:5.0, 2.5:7.5 and 0:10) constituted 6 and 10% of the reinforcing phase with the matrix material of Al-Mg-Si produced via two-step stir casting technique, the percentage elongation improved marginally and was generally invariant to increasing GSA content while the fracture toughness increased with increasing GSA content, hardness and tensile strength increases with increasing weight percent of the reinforcing phase but the strength and hardness dropped slightly with an increase in GSA content in the reinforcing phase. Haider et al. [21] showed the significant effect of the hard ceramics SiC and Al2 O3 by stir casting route, the results indicated that the developed successfully and there is an increase in the value of tensile strength, hardness and impact strength. Raju et al. [22] studied the surface roughness of pure commercial Al and Al-15% coconut shell ash (CSA)
4768
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
Table 1 – Chemical compositions of Al 6063 alloy. Elements
Si
Mg
Fe
Sn
Ti
Mn
Cr
Al
Amount (wt.%)
0.44
0.40
0.17
0.03
0.03
0.01
0.01
98.91
Fig. 1 – (a) MA, (b) NFC, (c) MCA and (d) SA.
Table 4 – Chemical compositions of MCA.
Table 2 – Chemical compositions of MA. Elements
Al2 O3
Fe2 O3
Elements
Fixed carbon
Volatile matter
Amount (wt.%)
90
10
Amount (wt.%)
72 Min
4 Max
Table 3 – Chemical compositions of NFC. Elements
SiO2
Cr2 O3
Amount (wt.%)
70
30
composite by stir casting method, the results of machining parameters such as cutting speed, feed rate and depth of cut on surface roughness were analyzed and become improvement on surface roughness. The mechanical properties and machining test experiments of the new generation of metal matrix composites have been performed and compared to the base Al 6063 alloys via stir casting process. The aim of this paper was used ceramics reinforced MA and NFC which is used as new reinforcement and compared it with synthetic waste met coke ash and new agro-waste straw ash reinforcements MCA and SA respectively. The results show good agreement and improvement in hardness, impact and tensile strength. Aluminum matrix composites which manufactured in this study have many applications in a wide range in mechanical components and in vehicle parts such as pillars, bumper beam, and crush box because aluminum matrix composites are making the vehicles lighter, safer and more fuel-efficient. We use Aluminum matrix composites in this study because we have many reasons to define this type as appropriate composite; these reasons are (high hardness to density and good resistance to impact strength). On the other hand, it can be recycling the useless ceramics, synthetic and agro wastes as reinforced materials.
3.
Experimental work and procedure
3.1.
Base metal
In this research, the material matrix alloy is Al 6063. The chemical compositions of Al 6063 alloy are shown in Table 1.
Elements
Ash
Moisture
Sulfur
Amount (wt.%)
24 Max
2 Max
0.70 Max
Table 5 – Chemical compositions of SA. Elements
Cu
Ni
Mn
Co
Pb
Fe
Amount (wt.%)
46.42
37.04
13.83
1.78
0.53
0.40
3.2.
Reinforcement materials
In selection of reinforcement material for aluminum we must considered some important facts and properties such as density, wettability, and thermal stability, two types of ceramics and one type of synthetic and also one type of waste vegetable which is wheat straw materials are used as reinforced metals such as MA, NFC, MCA and SA as shown in Fig. 1. Chemical compositions of all four types of reinforcement materials are tabulated in Tables 2,3,4 and 5.
3.3.
Processing of metal matrix composites
Aluminum 6063 alloy ingots were used as the matrix material and reinforced particles required having 5 wt. % volume percent were evaluated using charge calculations. The reinforced particles were initially preheated at a temperature of 500 ◦ C by using an analog electric furnace to help improve wettability with the Aluminum 6063 alloy for 30 minutes. The Aluminum 6063 ingots were charged into a digital electric furnace and heated to a temperature of 750 ± 30 ◦ C. The preheated reinforced particles were added at this temperature and stirring of the slurry was performed by using modified two-step mechanical stirrer and having three blades at each step. The stirring operation speed and time were performed 360 rpm and 10 minutes respectively to help improve the distribution of the reinforced particles in the molten aluminum 6063 alloys. Finally, the molten composite slurry was poured into the steel mold to solidify. A schematic view of the stir
4769
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
Fig. 2 – (a) Two step stirrer (b) Experimental techniques.
Table 6 – Al 6063 alloy and their constituents.
Table 7 – Experimental conditions summary.
SN
Sample detail compositions
Workpiece
1 2 3 4 5 6
Al 6063 Al 6063 + 5 wt.% MA Al 6063 + 5 wt.% MCA Al 6063 + 5 wt.% NFC Al 6063 + 5 wt.% SA Al 6063 + 5 wt. % MA + 5 wt. % NFC + 5 wt. % MCA + 5 wt. % SA
Lathe used Insert used
casting set up and two-step stirrer shown in Fig. 2. The constituent of Al 6063 alloy and its sample detail compositions shown in Table 6.
3.4.
Machinability conditions and their levels
The machining experiments were carried out on a TAKISAWA SL-360 type center lathe machine using coated carbide inserts. The machining process was conducted on all ten samples of MMCs which were cast without using cooling or any lubricant (dry turning) and samples length of 35 mm was kept for each machining process during surface roughness measurements. The size of the workpiece is 28 mm (diameter) × 220 mm (length). The average surface roughness (Ra) was measured by a TAYLOR–HOBSON (10) type instrument. A summary of the experimental conditions is provided in Table 7.
4.
Results and discussion
4.1.
Microstructural evaluation
A scanning electron microscope (SEM) was used to show photographically and studies the distribution analysis of Al 6063
Cutting speed (m/min) Feed rate (mm/rev) Depth of cut (mm) Tool overhang (mm) Measuring instrument Workpiece overhang (mm) Cutting condition
Bar size: diameter 28 mm × length 220 mm Machining length =35 mm TAKISAWA SL-360 type center Coated carbide insert cutting tool, tool nose radius =0.8 mm 10, 23, 37, 60, and 90 0.2 0.5 20 A TAYLOR–HOBSON (10) type 45 Dry turning (without using cooling or any lubricant)
alloy and all four types of reinforced metals in the aluminum matrix as in Fig. 3. The microstructure results indicate that the method used in the preparation of the composite was successful and this was reflected in the morphology and relatively uniform distribution of the particulates within the matrix. This figure shows the presence of equiaxed grains, which is attributed to the effect of stirring action which breaks the dendrite shaped structure and leaves the structure in an equiaxed form with fine intermetallic precipitates which seen in the matrix of Al. The investigation of a composite material of this work was made by the high precision technique process to cast suitable microstructure of the matrix with homogeneous particle distribution. The microstructure electron images of all the composites and the appearance of chemical homogeneities such as reinforcement/matrix interface with fewer inclusions make a good distribution of MMCs and forming composites with small grain size and uniform mechanical properties especially samples 6 (higher reinforcement level), large grain size
4770
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
Fig. 3 – Represented photomicrography of scanning electron microscope of the all test samples.
Table 8 – Results of mechanical properties of Al 6063 and their constituents. Sample detail compositions
Vickers hardness (kg/mm2 )
Impact strength (J)
UTS (MPa)
YTS (MPa)
Elongation(%)
Al 6063 Al 6063 + 5 wt.% MA Al 6063 + 5 wt.% MCA Al 6063 + 5 wt.% NFC Al 6063 + 5 wt.% SA Al 6063 + 5 wt. % MA + 5 wt. % NFC + 5 wt. % MCA + 5 wt. % SA
50.36 62.63 53.47 56.11 54.69 54.44
7.32 12.35 9.78 9.24 12.10 11.05
130 166 153 137 169 179
95 113 103 107 119 125
23 12 14 16 13 9
or structure sample 3 were observed with some agglomeration of reinforcement which produced highly isotropic behavior of the composite materials which further tend to decrease the mechanical properties. The reinforced particles are used in the present study have a good mixing, gathering, and bonding through grains to make a strong quantify uniform boundary particle distribution. This strong particle boundary causes a huge place inside the aluminum matrix.
4.2.
Mechanical properties
Mechanical properties tests were carried out at room temperature by using TERCO MT 3037 Universal Testing Machine with standard dimensions of specimen for tensile test.
The hardness and impact strength of the samples for all conditions were measured using the AVK Hardness Testing Machine and WP400 Pendulum Impact Instrument, respectively. The standard measurements for the tensile and impact test samples were ASTM A370 and ASTM E23 respectively. All the experimental test results of this research come at least from an average of three experiments. The observation results of the mechanical properties shown in Table 8. This table shows that mechanical properties of pure Al alloy and composites produced by stir casting, all these properties increased by adding additives compared to unreinforced alloy. The largest increased in mechanical properties was found in sample 6, the presence of all reinforcement together in the microstructure could impede the movement of dislocation
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
4771
Fig. 4 – Typical stress–strain curves of all test samples. Fig. 7 – Variation of yield and ultimate tensile strength for the all composites.
Fig. 5 – Vickers hardness for the all composites.
Fig. 8 – Variation of elongation for the all composites.
Fig. 6 – Impact strength for the all composites.
since ceramic particles are stronger than the matrix in which they are embedded, also have a solid lubricating effect due to the similar hexagonal closed packed structure. Using MCA as a reinforcement material sample 3 in Al alloy reduces tensile strength and hardness of the composites due to the segregation and particle clustering of MCA in the Al matrix when compared it with other reinforcements. Fig. 4 shows the typical stress-strain curves of Al 6063, MA, NFC, MCA, and SA with constant rate contents of 5 wt.% as in Table 8. Fig. 4 shows the
Fig. 9 – Effect of cutting speed on average chip length.
performance improvement of ultimate tensile stress. For the Al matrix, the elongation increases with a low rate of mechanical properties. For composites, the value of the tensile strength increase due to mixing additive metals such as ceramics, synthetic and waste vegetable, and also increase due to a better distribution of microstructure by stirring method and less containing of porosities and inclusions inside the grain structure.
4772
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
Table 9 – The measured length of chip shape style. Sample detail compositions
Vc = 10 m/min
Al 6063 Al 6063 + 5 wt.% MA Al 6063 + 5 wt.% MCA Al 6063 + 5 wt.% NFC Al 6063 + 5 wt.% SA Al 6063 + 5 wt. % MA + 5 wt. % NFC + 5 wt. % MCA + 5 wt. % SA
Vc = 90 m/min
Lmin (mm)
Lmax (mm)
La (mm)
R (-)
Lmin (mm)
Lmax (mm)
La (mm)
R (-)
4 3 5 11 4 4
12 7 10 45 10 9
8 5 7.5 28 7 6.5
9.9 9.4 6.7 8.4 8.9 7.3
19 29 27 26 23 7
53 115 71 107 85 17
36 72 49 66 54 12
7.7 8.3 6.3 8 8.9 7.5
Fig. 10 – Chip formation style shape for all samples during cutting speed of 10 m/min.
Several experiments of mechanical properties such as hardness, impact, elongation, yield and ultimate tensile strength are carried out to get the best optimize results of mixing process by stir casting route. Figs. 5, 6, 7 and 8 show the variation of mechanical properties of Al 6063 alloy and its composites. Fig. 5 shows the behavior of vickers hardness of metal matrix composites and Al 6063 alloy. The results show a good difference between the base metal Al 6063 alloy and Al 6063 metal matrix composites, which presents that the additional metals have an excellent changing in the results. MA has great effect of increasing the hardness followed by NFC, which
also has a good changing for increasing the hardness because MA and NFC were ceramic metal and have a high melting temperature. The result of hardness due to adding MA was 62.63 kg/mm2 as in sample 2, but the bad result of hardness was due to adding the synthetic metal MCA as in sample 3 is 53.47 kg/mm2 . Fig. 6 illustrates the impact strength of all composites. The results of impact strength were different compared to the results of hardness, samples 2, 5 and 6 have more effective for increased impact strength, here you would prefer when mixing all elements of reinforced metals together such as in sample 6. From the results, we can show that the mortar
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
4773
Fig. 11 – Chip formation style shape for all samples during cutting speed of 90 m/min.
ceramic and vegetable have the main role in increasing the impact strength. The variation of yield and ultimate tensile strength for all composites are plotted in Fig. 7. Sample 6 had maximum values of YTS and UTS compared to other samples, and the results were 125 and 179 MPa respectively, this increase due to strong, compact bonding of grains and good grain boundary distribution of this type of composite material as indicated in microstructure evaluation in Fig. 3 sample 6. All types of reinforced metal are using in this research have an excellent changing in the results of YTS and UTS compared to base metal Al 6063 alloy. The second effect is SA, which increases YTS and UTS as in sample 5, this phenomenon is showed that the vegetable reinforced metal has great benefit for increasing these properties of Al 6063 alloy. In this context, Joseph [23] show that the agro wastes in the form of powdery particulates have demonstrated great reinforcing abilities and they enhanced the mechanical properties of the various composite developed in comparison to the as-cast materials. Fig. 8 shows the variation of elongation for the all composites, the elongation decreases approximately in the range of 30 to 60 % compared with that of Al 6063 alloy under optimum constant values of reinforced metals. The less decrease
of elongation was by NFC as in sample 4 due to its chemical composition, but in general, the reduction of elongation achieved when all four types of reinforced metal mixing with a constant amount as in sample 6. The results above showed that the ceramic, synthetic, and waste vegetable reinforced metals have a perfect effect of changing the mechanical properties of Al 6063 alloy.
4.3.
Chip formation style
The chip formation style and its volume that is involved as plastic deformation phenomena during the shear zone. The chip volume ratio is the uncut chip thickness/chip thickness; the uncut chip thickness is the feed value in orthogonal cutting and can directly measure the chip thickness after cutting. Table 9 shows the length of chip shape style and chip volume ratio at cutting speed of 10 and 90 m/min. In this study, the chip shape formation and its volume were studied with respect to two different cutting speeds at the constant of feed rate and depth of cut. The all values of chip volume ratio in this work are in the acceptable rating, and it’s in the range shape of spiral chip segments. The variation of chip volume ratio depends to the many factors such as cutting parameters, a cutting tool (insert type, cutting angles and nose radius),
4774
2.208 1.610 1.400 1.121 1.708 1.547 1.950 1.706 1.306 1.209 1.732 1.545 2.277 1.844 1.440 1.330 1.804 1.486 2.915 2.603 2.258 2.200 2.639 2.429 2.692 2.550 2.177 2.012 2.576 2.403 2.947 2.712 2.290 2.182 2.631 2.504 3.106 2.547 2.307 2.406 2.710 2.380 3.540 3.110 2.523 2.497 3.123 2.696 3.500 3.026 2.490 2.563 3.092 2.722 3.483 3.147 2.496 2.542 3.192 2.750 3.637 3.157 2.583 2.386 3.085 2.616 4.393 3.783 3.372 3.433 3.972 3.457 4.411 3.850 3.414 3.454 4.143 3.541 4.307 3.673 3.529 3.461 3.926 3.548 4.461 3.826 3.173 3.384 3.847 3.372 4.906 4.641 4.279 4.326 4.734 4.387 4.877 4.643 4.343 4.252 4.719 4.288 4.852 4.523 4.175 4.301 4.804 4.393 4.989 4.759 4.319 4.425 4.679 4.480 1 2 3 4 5 6
R3 (m) R2 (m) R2 (m) R1 (m) Ra (m) R3 (m) R2 (m) R1 (m) Ra (m) R3 (m) R2 (m) R1 (m)
R2 (m)
R3 (m)
Ra (m)
R1 (m)
Vc = 23 m/min Vc =10 m/min SN
A TAYLOR–HOBSON (10) type instrument was used and shown in Fig. 12. It consists of a probe surface roughness calculating device connected to it. This device has two ways of reading the surface roughness, first is reading the average surface roughness Ra directly from the gauge, and the second is drawing the surface texture profile. The range of the device is reading from (0.01 m to 5 m), and the range of drawing the profile is from (0.04 m to 60 m). Table 10 shows the average surface roughness during five different cutting speeds. The outcome of average surface roughness has been employed to optimize the turning parameters for selecting the best type and amount of reinforcement material. The optimum values of average surface roughness within the different cutting speed and sample detail composition are showed completely in Fig. 13. The average surface roughness was measured for all experiments. The effects of the input parameters such as cutting speeds (10, 23, 37, 60, and 90 m/min) on the average surface roughness are shown in Table 10. Fig. 13 shows the effect of cutting speed on average surface roughness within different sample detail composition. It is seen from these values that the average surface roughness Ra is decreased with increasing particles volume fraction. It should be noted from the results of average surface roughness, that the NFC has decreased Ra dramatically for all cutting speeds due to its small and good bonding of structures containing of SiO2 and Cr2 O3 and followed by MCA it ranked the second one to improve Ra, but the MA and SA have less effect on Ra compared to NFC and
R3 (m)
Ra (m)
R1 (m)
Vc = 90 m/min Vc = 60 m/min Vc = 37 m/min
Surface roughness methodology
Table 10 – Experiments of average surface roughness.
4.4.
Ra (m)
cutting conditions and material types especially adding additives [24]. The planned experiment was also developed for the influence of cutting speeds on average chip style length La. Fig. 9 observed due to the presence of reinforced particle metal proceeded, it was found that La is maximum values when adding MA as in sample 2, because MA contains both aluminum and iron oxides, these two materials have high resistance and withstand to high cutting speed temperature between tool insert and workpiece, and it hindrance the separate of chip, so, for this reason, MA make longer chip compared to other reinforced metals. NFC, MCA, and SA are medium average chip length La at high cutting speed compared to MA, but sample 6 is not perfect for high cutting speed because all types of reinforcement together damage the chips and decrease the length of it. Fig. 9 also showed La at a low cutting speed of 10 m/min. NFC becomes the first best one for average chip length is followed by all other reinforcements due to low cutting speed and low cutting temperature, but MA is not perfect for high and low cutting speeds cutting. Figs. 10 and 11 showed chip formation style shape during cutting speeds of 10 and 90 m/min, respectively, the Figures showed three forms of chips as known as spring, semi-circle, and helical. The spring shape known as continuous chip and the others were semi-circle and helical known as discontinuous chip. It was found from Figs. 10 and 11; reinforced metals can change the chip style from discontinuous chip to continuous chip but in limited quality and quantity of reinforced metals.
2.145 1.720 1.382 1.220 1.748 1.526
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
4775
Fig. 12 – A TYLOR-HOBSON (10) surface roughness device.
Fig. 13 – Effect of cutting speed on average surface roughness within different sample detail compositions.
MCA due to its structure and grain size of MA and SA. From the results are shown in Table 10, the maximum and minimum values of Ra are (4.906 m and 1.220 m) at 10 m/min and 90 m/min respectively. So the best improvement of Ra is at cutting speed of 90 m/min. These means high cutting speed and low feed rate produced a better surface finish which leads to increase the tool life.
5.
Conclusions
In this study, Al 6063 alloy based composite reinforced particles are fabricated using two steps of techniques of the stir casting process. Details of the experimental investigation are
presented for the effects of different types of metal matrix composites on mechanical properties, microstructural observation, average surface roughness, and chip shape formation style. The conclusions of the results in this investigation study can be summarized in the following points: 1. Aluminum alloy composites were successfully produced by liquid stir casting technique by adding ceramics, synthetic, and waste vegetable reinforcement in 6063 Al alloy to produced metal matrix composite. 2. The main properties of the MMCs are mainly depending on the microstructural parameters of the reinforcing materials type and volume fraction. Stir casting technique which is used in this paper produces compact grain boundary,
4776
3.
4.
5.
6.
7.
8.
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
smaller, stronger and uniform distribution grain size with good interface bonding of particulate matrix. The YTS and UTS, which obtained from the results of MMCs, are much more than Al 6063 alloy especially when adding all four types of composites together. The effect of NFC for increasing YTS and UTS is very less compared with other types of reinforced metal due to its chemical composition (Cr2 O3 ). The hardness of the MMCs is higher than Al 6063 alloy and the cast of ceramic additives MA composite increasing hardness more than the other types of MMCs due to the high atomic bonding between the atoms. Experimental results show that the impact strength increased by adding MA and SA reinforcements respectively, while, the less decrease of elongation was by NFC and MCA. All four types of additives will be given a high acceptable standard range of chip volume ratio. On the other hand, the chip length increases by NFC during cutting speed of 10 m/min, but within cutting speed of 90 m/min, MA has an important role to change the length and formation style of the chip from discontinuous chip to continuous chip. The machinability of MMCs is different from the traditional materials because of the presence of reinforcement particles, during turning operation the surface roughness is decreased by adding NFC and MCA especially when the velocity changed from10 m/min to 90 m/min, it means high velocity produced a better surface finish which leads to long tool life. The advent of the importance of new agricultural waste SA in particulate form as a reinforcement for MMCs is not just of added advantage to our manufacturing industries because of its availability and low cost, but it also reduces the rate of environmental pollution by converting such waste from agro processes into useful raw materials for engineering purposes.
Conflicts of interest The authors declare no conflicts of interest.
Acknowledgments This study was mainly supported by the Department of Mechanical & Mechatronics Engineering, College of Engineering, Salahaddin University-Erbil, Ministry of Higher Education and Scientific Research, Kurdistan Regional Government (KRG), Iraq.
references
[1] Venkatesulu M, Ramakotaiah K. Production and mechanical properties of Al 6063/B4C composites. J Mech Eng Res Dev 2019;42(1):46–9, http://dx.doi.org/10.26480/jmerd.01.2019.46.49. [2] Alkadir I, Salim L. Effect of B4 C/fly ash addition on wear and mechanical properties of Al-Cu-Mg alloy. Eng Technol J 2017;35(4):301–10.
[3] Aniban N, Pillai R, Pai B. An analysis of impeller parameters for aluminum metal matrix composites synthesis. Mater Des 2002;23(1):553–6, http://dx.doi.org/10.1016/S0261-3069(02)00024-9. [4] Tzamtzis S, Barker N, Babu N, Patel J, Dhindaw B, Fan Z. Processing of advanced Al/SiC particulate metal matrix composites under intensive shearing–A novel rheo-process. Composite Appl Sci Manufacturing 2009;40(1):144–51, http://dx.doi.org/10.1016/j.compositesa.2008.10.017. [5] Canakci A, Ozashin S, Varol T. Prediction of effect of reinforcement size and volume fraction on the abrasive wear behavior of AA2014/B4 Cp MMCs using artificial neural network. Arab J Sci Eng 2014;39(8):6351–61, http://dx.doi.org/10.1007/s13369-014-1157-9. [6] George P, Kantharaj I, Mohanasundaram S, Rao G. Experimental investigation on the mechanical properties of LM6 aluminum alloy reinforced with boron carbide and titanium hybrid composites. Int J Mech Eng Technol 2019;10(2):1584–93. [7] Kathiresan M, Theerkkatharisanan R, Rajan A. Optimization of hybrid aluminum metal matrix composite through taguchi method. Int Res J Eng Technol 2017;4(3):569–74. [8] Lakshmipathy J, Kulendran B. Reciprocating wear behavior of 7075Al/SiC and 6061Al/Al2O3 composites: a study of effect of reinforcement, stroke and load. Tribol Ind 2014;36(2):117–26. [9] Bhadare R, Sonawane P. Preparation of aluminum matrix composite by using stir casting method. Int J Eng Adv Technol 2013;3(2):61–5. [10] Ashofteh A, Mashhadi M, Amadeh A. Thermal shock behavior of mixed composite top coat APS TBCs. Ceramics–Silikáty 2018;62(2):200–9, http://dx.doi.org/10.13168/cs.2018.0013. [11] Sozhamannan G, Balasivanandh S, Venkatagalapathy V. Effect of processing parameters on metal matrix composites: stir casting process. J Surf Eng Mater Adv Technol 2012;2(1):11–5, http://dx.doi.org/10.4236/jsemat.2012.21002. [12] Kumar A, Lal S, Kumar S. Fabrication and characterization of A359/Al2O3 metal matrix composite using electromagnetic stir casting method. J Mater Res Technol 2013;2(3):250–4, http://dx.doi.org/10.1016/j.jmrt.2013.03.015. [13] Alaneme K, Bodunrin M. Mechanical behavior of alumina reinforced AA6063 metal matrix composites developed by two step-stir casting process. ATCA Technica Corviniensis-Bull Eng 2013:105–10. ROMANIA. [14] Patel V, Goyal B, Shah C. Optimization of process parameters of CNC milling for aluminum metal matrix composite. Int Conf Multidiscip Res Pract 2014;1(8):394–9. INDIA. [15] Malaki M, Xu W, Kasar A, Menezes P, Diertinga H, Varma R, et al. Advanced metal matrix nanocomposites. Metals 2019;9(330), http://dx.doi.org/10.3390/met 9030330. [16] Bodunrin M, Alaneme K, Chown L. Aluminum matrix hybrid composites: a review of reinforcement philosophies; mechanical, corrosion and tribological characteristics. J Mater Res Technol 2015;4(4):434–45, http://dx.doi.org/10.1016/j.jmrt.2015.05.003. [17] Sood P, Sehgal R, Dwivedi K. Machinability of hypereutectic cast Al-Si alloys processed by SSM processing technique. Indian Acad Sci 2017;42(3):365–78, http://dx.doi.org/10.1007/s12046-017-0609-9. [18] Hindi J, Kini U, Sharma S, Gurumurthy B, Shankar M. Mechanical characterization of stir cast Al 6063 matrix SiC reinforced metal matrix composite. In: 5th International Conference on Automotive, Mechanical and Materials Engineering. 2015. p. 69–73. [19] Phanibhubshana V, Chandrappa C, Niranjan H. Evaluation of mechanical properties of Al 6061 reinforced with hematite. J Multidiscip Eng Sci Technol 2015;2(1):255–60. [20] Alaneme K, Bodunrin M, Awe A. Microstructure, mechanical and fracture properties of groundnut shell ash and silicon
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
carbide dispersion strengthened aluminum matrix composites. J King Saud Univ Eng Sci 2016;1(1):1–8, http://dx.doi.org/10.1016/j.jksues.2016.01.001. [21] Haider K, Alam M, Redhewal A, Saxena V. Investigation of mechanical properties of aluminum based metal matrix composites reinforced with SiC and Al2 O3 . Int J Eng Res Technol 2015;5(9):63–9. [22] Raju S, Rao G, Rao M. Optimization of machinability properties on aluminum metal matrix composites prepared
4777
by in-situ ceramic mixture using coconut shell ash-taguchi approach. Int J Conceptions Mech Civil Eng 2015;3(2):17–21. [23] Joseph O, Babarmu K. Agricultural waste as a reinforcement particulate for aluminum metal matrix composites (AMMCs): a review. Fibers 2019;7(33):1–9, http://dx.doi.org/10.3390/fib7040033. [24] Grote K, Antonsson E. Springer handbook of mechanical engineering. In: Springer Handbooks; 2009. p. 611–2. XXVII.
Available online at www.sciencedirect.com
www.jmrt.com.br
Original Article
Reinforcement and processing on the machinability and mechanical properties of aluminum matrix composites Fakhir Aziz Rasul Rozhbiany ∗ , Shawnim Rashied Jalal Department of Mechanical & Mechatronics Engineering, College of Engineering, Salahaddin University-Erbil, Erbil, Iraq
a r t i c l e
i n f o
a b s t r a c t
Article history:
Metal matrix composites are an essential product used in engineering materials. This prod-
Received 25 March 2019
uct has wide applications in automotive, aerospace, and other uses. In this paper, four
Accepted 16 August 2019
different reinforced such as (MA), (MCA), (NFC) and (SA) with a constant rate of 5 wt. %
Available online 30 August 2019
for each reinforced element used and mixed with Al 6063 alloy to produced composite by using modified two-step mechanical stirrer and having three blades at each step. Coated
Keywords:
carbide tool insert was carrying out the turning process. The chip volume ratio and chip
Mechanical properties
shape style formation were performed within cutting speeds of 10 and 90 m/min, which
Chip formation style
appears in different length and shapes especially at 90 m/min. The chip volume ratio is
Surface roughness
not increased by all four types of reinforced metal but still maintain in the standard range
Metal matrix composites (MMCs)
according to the shape of chips. NFC increasing average chip length during cutting speed of 10 m/min, but within cutting speed of 90 m/min, MA has an important role to change the volume and formation style of a chip from discontinuous chip to continuous chip. It should be noted from the results, that the NFC has decreased surface roughness dramatically for all cutting speeds and followed by MCA, but the MA and SA have less effect compared to NFC and MCA. The mechanical properties such as yield ultimate tensile strength and hardness of the composites are much more than Al 6063 alloy especially when adding all four types of reinforcement together moreover the effect of NFC is very less compared with other types of reinforced materials. MA increase hardness more than the different types of reinforcement. Microstructure observation produces compact grain boundaries with strong grains of metal matrix composites compared to Al 6063 alloys. © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
1.
∗
Introduction
Most of the researchers during the last three decades have been generated tremendous interested to use aluminum and its alloys due to their properties such as lightweight, excellent mechanical properties, low cost, good tribological properties,
Corresponding author. E-mail: [email protected] (F.A. Rozhbiany). https://doi.org/10.1016/j.jmrt.2019.08.023 2238-7854/© 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
Nomenclature Al MMCs MA NFC MCA SA SN Vc Ra La YTS UTS SEM R
Aluminum Metal matrix composites Mortar ash Nano fibrillated composite Met coke ash Straw ash Sample number Cutting speed Average surface roughness Average chip length Yield tensile strength Ultimate tensile strength Scanning electron microscope Chip volume ratio
good stiffness and best corrosion resistance compared to conventional metals [1–4]. So to perceived the improvement in the mechanical properties of Al alloy many additives were added and mixing with it to produced MMCs which consist of matrix and reinforcements. Composites are a unique class of materials invariably favored by nature in certain and humans from prehistoric times. Composites provide a unique capability of enhancing the selected properties of monolithic materials which remains superior to the monolithic counterparts. The enhancement in the targeted property of a metallic matrix can be controlled through the selection of types, size, volume fraction, orientation, microstructural parameters of the reinforcing materials, and the amount of reinforcement which forms the core of composite design in addition to the choice of matrix normally lightweight such as aluminum and magnesium and reinforcement such as nano-ceramic, nano oxides, carbon-based nano-allotropy, elements etc., the improvement in properties of MMCs crucially depends on the processing route and the processing parameters that can provide a uniform distribution of reinforcement and a good matrix-reinforcement interface [5,6]. Composites consist of metal matrix composites which have more characteristics such as better wear, fatigue, elastic properties, higher electric, and higher thermal conductivities and reinforced nanostructure which has low thermal conductivity and better shock resistance so composites give good combination of two or more materials to get best properties. Materials development has changed by shifting from monolithic to composite materials due to reduced weight, quality, high performance, and low cost. The design goal of composites is obtained by improved mechanical and functional properties [7–10]. Stir casting is a common, economical and relatively simple method to produce the MMCs called as materials system which has two or more micro/macro with different composition. Some properties of MMCs have better performance, high accuracy with a higher rate of production. An application of MMCs includes automotive area involves industrial applications because they have best properties. The homogeneous distributions of reinforcements in the matrix of processing
4767
MMCs are major challenges of production and it has a strong impact on the quality of properties and material [11–15].
2.
Literature review
Bodunrin et al. [16] developed many tested about agro wastes in MMCs include: bamboo leaf ash (BLA), rice husk ash (RHA), bagasse ash (BA), palm kernel shell ash (PKSA), maize stalk ash (MSA), corn cob ash (CCA), bean shell waste ash (BSWA) mentioned a few and the development of hybrid aluminum matrix composites (AMCs) with agro–waste ash serving as complementing reinforcement, agro waste has improvement for most properties of AMCs with single reinforced AMCs. Double synthetic reinforcement hybrid composites compared the mechanical properties obtain with unreinforced alloy rather than the single reinforced composite; therefore further investigation should be carried out to determine how much the mechanical properties are improved when comparing the hybrid composites with double synthetic reinforcement to single reinforced composites. Sood et al. [17] experimentally showed semi-solid metal processing carried out by mechanical stirring on the machinability studies of Al-20Si-0.5Mg-1.2Fe based alloy to determine the influence of cutting speed, feed rate and depth of cut by using the constant rate of beryllium and cadmium 0.03% as reinforced metal, the results show that the length of chip changed under different machining conditions, on the other hand, there is an improvement in the rate of surface roughness and cutting force. Hindi et al. [18] described ceramic material such as silicon carbide of 2, 4 and 6% as reinforcement are manufactured using conventional stir casting technique, the microstructure reveals better dispersion of reinforcement in the matrix, hardness and tensile strength of 6% SiC be higher than 2 & 4% but the ductility and the impact strength are improvements with 4% SiC. Phanibhubshana et al. [19] analyzed practically the application of varied rate of hematite also known as ferrous oxide (Fe2 O3 ) as reinforcement mixing with Al 6061 alloy by stir casting technique, hematite was added in different proportions 2, 4, 6 and 8, significant improvement in hardness and tensile strength were observed with the increase of hematite rate and microstructural studies showed better bonding and dispersion of the Fe2 O3 metal matrix composites. Alaneme et al. [20] investigated the combination of groundnut shell ash (GSA) and silicon carbide (SiC) with different mixing ratio (10:0, 7.5:2.5, 5.0:5.0, 2.5:7.5 and 0:10) constituted 6 and 10% of the reinforcing phase with the matrix material of Al-Mg-Si produced via two-step stir casting technique, the percentage elongation improved marginally and was generally invariant to increasing GSA content while the fracture toughness increased with increasing GSA content, hardness and tensile strength increases with increasing weight percent of the reinforcing phase but the strength and hardness dropped slightly with an increase in GSA content in the reinforcing phase. Haider et al. [21] showed the significant effect of the hard ceramics SiC and Al2 O3 by stir casting route, the results indicated that the developed successfully and there is an increase in the value of tensile strength, hardness and impact strength. Raju et al. [22] studied the surface roughness of pure commercial Al and Al-15% coconut shell ash (CSA)
4768
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
Table 1 – Chemical compositions of Al 6063 alloy. Elements
Si
Mg
Fe
Sn
Ti
Mn
Cr
Al
Amount (wt.%)
0.44
0.40
0.17
0.03
0.03
0.01
0.01
98.91
Fig. 1 – (a) MA, (b) NFC, (c) MCA and (d) SA.
Table 4 – Chemical compositions of MCA.
Table 2 – Chemical compositions of MA. Elements
Al2 O3
Fe2 O3
Elements
Fixed carbon
Volatile matter
Amount (wt.%)
90
10
Amount (wt.%)
72 Min
4 Max
Table 3 – Chemical compositions of NFC. Elements
SiO2
Cr2 O3
Amount (wt.%)
70
30
composite by stir casting method, the results of machining parameters such as cutting speed, feed rate and depth of cut on surface roughness were analyzed and become improvement on surface roughness. The mechanical properties and machining test experiments of the new generation of metal matrix composites have been performed and compared to the base Al 6063 alloys via stir casting process. The aim of this paper was used ceramics reinforced MA and NFC which is used as new reinforcement and compared it with synthetic waste met coke ash and new agro-waste straw ash reinforcements MCA and SA respectively. The results show good agreement and improvement in hardness, impact and tensile strength. Aluminum matrix composites which manufactured in this study have many applications in a wide range in mechanical components and in vehicle parts such as pillars, bumper beam, and crush box because aluminum matrix composites are making the vehicles lighter, safer and more fuel-efficient. We use Aluminum matrix composites in this study because we have many reasons to define this type as appropriate composite; these reasons are (high hardness to density and good resistance to impact strength). On the other hand, it can be recycling the useless ceramics, synthetic and agro wastes as reinforced materials.
3.
Experimental work and procedure
3.1.
Base metal
In this research, the material matrix alloy is Al 6063. The chemical compositions of Al 6063 alloy are shown in Table 1.
Elements
Ash
Moisture
Sulfur
Amount (wt.%)
24 Max
2 Max
0.70 Max
Table 5 – Chemical compositions of SA. Elements
Cu
Ni
Mn
Co
Pb
Fe
Amount (wt.%)
46.42
37.04
13.83
1.78
0.53
0.40
3.2.
Reinforcement materials
In selection of reinforcement material for aluminum we must considered some important facts and properties such as density, wettability, and thermal stability, two types of ceramics and one type of synthetic and also one type of waste vegetable which is wheat straw materials are used as reinforced metals such as MA, NFC, MCA and SA as shown in Fig. 1. Chemical compositions of all four types of reinforcement materials are tabulated in Tables 2,3,4 and 5.
3.3.
Processing of metal matrix composites
Aluminum 6063 alloy ingots were used as the matrix material and reinforced particles required having 5 wt. % volume percent were evaluated using charge calculations. The reinforced particles were initially preheated at a temperature of 500 ◦ C by using an analog electric furnace to help improve wettability with the Aluminum 6063 alloy for 30 minutes. The Aluminum 6063 ingots were charged into a digital electric furnace and heated to a temperature of 750 ± 30 ◦ C. The preheated reinforced particles were added at this temperature and stirring of the slurry was performed by using modified two-step mechanical stirrer and having three blades at each step. The stirring operation speed and time were performed 360 rpm and 10 minutes respectively to help improve the distribution of the reinforced particles in the molten aluminum 6063 alloys. Finally, the molten composite slurry was poured into the steel mold to solidify. A schematic view of the stir
4769
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
Fig. 2 – (a) Two step stirrer (b) Experimental techniques.
Table 6 – Al 6063 alloy and their constituents.
Table 7 – Experimental conditions summary.
SN
Sample detail compositions
Workpiece
1 2 3 4 5 6
Al 6063 Al 6063 + 5 wt.% MA Al 6063 + 5 wt.% MCA Al 6063 + 5 wt.% NFC Al 6063 + 5 wt.% SA Al 6063 + 5 wt. % MA + 5 wt. % NFC + 5 wt. % MCA + 5 wt. % SA
Lathe used Insert used
casting set up and two-step stirrer shown in Fig. 2. The constituent of Al 6063 alloy and its sample detail compositions shown in Table 6.
3.4.
Machinability conditions and their levels
The machining experiments were carried out on a TAKISAWA SL-360 type center lathe machine using coated carbide inserts. The machining process was conducted on all ten samples of MMCs which were cast without using cooling or any lubricant (dry turning) and samples length of 35 mm was kept for each machining process during surface roughness measurements. The size of the workpiece is 28 mm (diameter) × 220 mm (length). The average surface roughness (Ra) was measured by a TAYLOR–HOBSON (10) type instrument. A summary of the experimental conditions is provided in Table 7.
4.
Results and discussion
4.1.
Microstructural evaluation
A scanning electron microscope (SEM) was used to show photographically and studies the distribution analysis of Al 6063
Cutting speed (m/min) Feed rate (mm/rev) Depth of cut (mm) Tool overhang (mm) Measuring instrument Workpiece overhang (mm) Cutting condition
Bar size: diameter 28 mm × length 220 mm Machining length =35 mm TAKISAWA SL-360 type center Coated carbide insert cutting tool, tool nose radius =0.8 mm 10, 23, 37, 60, and 90 0.2 0.5 20 A TAYLOR–HOBSON (10) type 45 Dry turning (without using cooling or any lubricant)
alloy and all four types of reinforced metals in the aluminum matrix as in Fig. 3. The microstructure results indicate that the method used in the preparation of the composite was successful and this was reflected in the morphology and relatively uniform distribution of the particulates within the matrix. This figure shows the presence of equiaxed grains, which is attributed to the effect of stirring action which breaks the dendrite shaped structure and leaves the structure in an equiaxed form with fine intermetallic precipitates which seen in the matrix of Al. The investigation of a composite material of this work was made by the high precision technique process to cast suitable microstructure of the matrix with homogeneous particle distribution. The microstructure electron images of all the composites and the appearance of chemical homogeneities such as reinforcement/matrix interface with fewer inclusions make a good distribution of MMCs and forming composites with small grain size and uniform mechanical properties especially samples 6 (higher reinforcement level), large grain size
4770
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
Fig. 3 – Represented photomicrography of scanning electron microscope of the all test samples.
Table 8 – Results of mechanical properties of Al 6063 and their constituents. Sample detail compositions
Vickers hardness (kg/mm2 )
Impact strength (J)
UTS (MPa)
YTS (MPa)
Elongation(%)
Al 6063 Al 6063 + 5 wt.% MA Al 6063 + 5 wt.% MCA Al 6063 + 5 wt.% NFC Al 6063 + 5 wt.% SA Al 6063 + 5 wt. % MA + 5 wt. % NFC + 5 wt. % MCA + 5 wt. % SA
50.36 62.63 53.47 56.11 54.69 54.44
7.32 12.35 9.78 9.24 12.10 11.05
130 166 153 137 169 179
95 113 103 107 119 125
23 12 14 16 13 9
or structure sample 3 were observed with some agglomeration of reinforcement which produced highly isotropic behavior of the composite materials which further tend to decrease the mechanical properties. The reinforced particles are used in the present study have a good mixing, gathering, and bonding through grains to make a strong quantify uniform boundary particle distribution. This strong particle boundary causes a huge place inside the aluminum matrix.
4.2.
Mechanical properties
Mechanical properties tests were carried out at room temperature by using TERCO MT 3037 Universal Testing Machine with standard dimensions of specimen for tensile test.
The hardness and impact strength of the samples for all conditions were measured using the AVK Hardness Testing Machine and WP400 Pendulum Impact Instrument, respectively. The standard measurements for the tensile and impact test samples were ASTM A370 and ASTM E23 respectively. All the experimental test results of this research come at least from an average of three experiments. The observation results of the mechanical properties shown in Table 8. This table shows that mechanical properties of pure Al alloy and composites produced by stir casting, all these properties increased by adding additives compared to unreinforced alloy. The largest increased in mechanical properties was found in sample 6, the presence of all reinforcement together in the microstructure could impede the movement of dislocation
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
4771
Fig. 4 – Typical stress–strain curves of all test samples. Fig. 7 – Variation of yield and ultimate tensile strength for the all composites.
Fig. 5 – Vickers hardness for the all composites.
Fig. 8 – Variation of elongation for the all composites.
Fig. 6 – Impact strength for the all composites.
since ceramic particles are stronger than the matrix in which they are embedded, also have a solid lubricating effect due to the similar hexagonal closed packed structure. Using MCA as a reinforcement material sample 3 in Al alloy reduces tensile strength and hardness of the composites due to the segregation and particle clustering of MCA in the Al matrix when compared it with other reinforcements. Fig. 4 shows the typical stress-strain curves of Al 6063, MA, NFC, MCA, and SA with constant rate contents of 5 wt.% as in Table 8. Fig. 4 shows the
Fig. 9 – Effect of cutting speed on average chip length.
performance improvement of ultimate tensile stress. For the Al matrix, the elongation increases with a low rate of mechanical properties. For composites, the value of the tensile strength increase due to mixing additive metals such as ceramics, synthetic and waste vegetable, and also increase due to a better distribution of microstructure by stirring method and less containing of porosities and inclusions inside the grain structure.
4772
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
Table 9 – The measured length of chip shape style. Sample detail compositions
Vc = 10 m/min
Al 6063 Al 6063 + 5 wt.% MA Al 6063 + 5 wt.% MCA Al 6063 + 5 wt.% NFC Al 6063 + 5 wt.% SA Al 6063 + 5 wt. % MA + 5 wt. % NFC + 5 wt. % MCA + 5 wt. % SA
Vc = 90 m/min
Lmin (mm)
Lmax (mm)
La (mm)
R (-)
Lmin (mm)
Lmax (mm)
La (mm)
R (-)
4 3 5 11 4 4
12 7 10 45 10 9
8 5 7.5 28 7 6.5
9.9 9.4 6.7 8.4 8.9 7.3
19 29 27 26 23 7
53 115 71 107 85 17
36 72 49 66 54 12
7.7 8.3 6.3 8 8.9 7.5
Fig. 10 – Chip formation style shape for all samples during cutting speed of 10 m/min.
Several experiments of mechanical properties such as hardness, impact, elongation, yield and ultimate tensile strength are carried out to get the best optimize results of mixing process by stir casting route. Figs. 5, 6, 7 and 8 show the variation of mechanical properties of Al 6063 alloy and its composites. Fig. 5 shows the behavior of vickers hardness of metal matrix composites and Al 6063 alloy. The results show a good difference between the base metal Al 6063 alloy and Al 6063 metal matrix composites, which presents that the additional metals have an excellent changing in the results. MA has great effect of increasing the hardness followed by NFC, which
also has a good changing for increasing the hardness because MA and NFC were ceramic metal and have a high melting temperature. The result of hardness due to adding MA was 62.63 kg/mm2 as in sample 2, but the bad result of hardness was due to adding the synthetic metal MCA as in sample 3 is 53.47 kg/mm2 . Fig. 6 illustrates the impact strength of all composites. The results of impact strength were different compared to the results of hardness, samples 2, 5 and 6 have more effective for increased impact strength, here you would prefer when mixing all elements of reinforced metals together such as in sample 6. From the results, we can show that the mortar
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
4773
Fig. 11 – Chip formation style shape for all samples during cutting speed of 90 m/min.
ceramic and vegetable have the main role in increasing the impact strength. The variation of yield and ultimate tensile strength for all composites are plotted in Fig. 7. Sample 6 had maximum values of YTS and UTS compared to other samples, and the results were 125 and 179 MPa respectively, this increase due to strong, compact bonding of grains and good grain boundary distribution of this type of composite material as indicated in microstructure evaluation in Fig. 3 sample 6. All types of reinforced metal are using in this research have an excellent changing in the results of YTS and UTS compared to base metal Al 6063 alloy. The second effect is SA, which increases YTS and UTS as in sample 5, this phenomenon is showed that the vegetable reinforced metal has great benefit for increasing these properties of Al 6063 alloy. In this context, Joseph [23] show that the agro wastes in the form of powdery particulates have demonstrated great reinforcing abilities and they enhanced the mechanical properties of the various composite developed in comparison to the as-cast materials. Fig. 8 shows the variation of elongation for the all composites, the elongation decreases approximately in the range of 30 to 60 % compared with that of Al 6063 alloy under optimum constant values of reinforced metals. The less decrease
of elongation was by NFC as in sample 4 due to its chemical composition, but in general, the reduction of elongation achieved when all four types of reinforced metal mixing with a constant amount as in sample 6. The results above showed that the ceramic, synthetic, and waste vegetable reinforced metals have a perfect effect of changing the mechanical properties of Al 6063 alloy.
4.3.
Chip formation style
The chip formation style and its volume that is involved as plastic deformation phenomena during the shear zone. The chip volume ratio is the uncut chip thickness/chip thickness; the uncut chip thickness is the feed value in orthogonal cutting and can directly measure the chip thickness after cutting. Table 9 shows the length of chip shape style and chip volume ratio at cutting speed of 10 and 90 m/min. In this study, the chip shape formation and its volume were studied with respect to two different cutting speeds at the constant of feed rate and depth of cut. The all values of chip volume ratio in this work are in the acceptable rating, and it’s in the range shape of spiral chip segments. The variation of chip volume ratio depends to the many factors such as cutting parameters, a cutting tool (insert type, cutting angles and nose radius),
4774
2.208 1.610 1.400 1.121 1.708 1.547 1.950 1.706 1.306 1.209 1.732 1.545 2.277 1.844 1.440 1.330 1.804 1.486 2.915 2.603 2.258 2.200 2.639 2.429 2.692 2.550 2.177 2.012 2.576 2.403 2.947 2.712 2.290 2.182 2.631 2.504 3.106 2.547 2.307 2.406 2.710 2.380 3.540 3.110 2.523 2.497 3.123 2.696 3.500 3.026 2.490 2.563 3.092 2.722 3.483 3.147 2.496 2.542 3.192 2.750 3.637 3.157 2.583 2.386 3.085 2.616 4.393 3.783 3.372 3.433 3.972 3.457 4.411 3.850 3.414 3.454 4.143 3.541 4.307 3.673 3.529 3.461 3.926 3.548 4.461 3.826 3.173 3.384 3.847 3.372 4.906 4.641 4.279 4.326 4.734 4.387 4.877 4.643 4.343 4.252 4.719 4.288 4.852 4.523 4.175 4.301 4.804 4.393 4.989 4.759 4.319 4.425 4.679 4.480 1 2 3 4 5 6
R3 (m) R2 (m) R2 (m) R1 (m) Ra (m) R3 (m) R2 (m) R1 (m) Ra (m) R3 (m) R2 (m) R1 (m)
R2 (m)
R3 (m)
Ra (m)
R1 (m)
Vc = 23 m/min Vc =10 m/min SN
A TAYLOR–HOBSON (10) type instrument was used and shown in Fig. 12. It consists of a probe surface roughness calculating device connected to it. This device has two ways of reading the surface roughness, first is reading the average surface roughness Ra directly from the gauge, and the second is drawing the surface texture profile. The range of the device is reading from (0.01 m to 5 m), and the range of drawing the profile is from (0.04 m to 60 m). Table 10 shows the average surface roughness during five different cutting speeds. The outcome of average surface roughness has been employed to optimize the turning parameters for selecting the best type and amount of reinforcement material. The optimum values of average surface roughness within the different cutting speed and sample detail composition are showed completely in Fig. 13. The average surface roughness was measured for all experiments. The effects of the input parameters such as cutting speeds (10, 23, 37, 60, and 90 m/min) on the average surface roughness are shown in Table 10. Fig. 13 shows the effect of cutting speed on average surface roughness within different sample detail composition. It is seen from these values that the average surface roughness Ra is decreased with increasing particles volume fraction. It should be noted from the results of average surface roughness, that the NFC has decreased Ra dramatically for all cutting speeds due to its small and good bonding of structures containing of SiO2 and Cr2 O3 and followed by MCA it ranked the second one to improve Ra, but the MA and SA have less effect on Ra compared to NFC and
R3 (m)
Ra (m)
R1 (m)
Vc = 90 m/min Vc = 60 m/min Vc = 37 m/min
Surface roughness methodology
Table 10 – Experiments of average surface roughness.
4.4.
Ra (m)
cutting conditions and material types especially adding additives [24]. The planned experiment was also developed for the influence of cutting speeds on average chip style length La. Fig. 9 observed due to the presence of reinforced particle metal proceeded, it was found that La is maximum values when adding MA as in sample 2, because MA contains both aluminum and iron oxides, these two materials have high resistance and withstand to high cutting speed temperature between tool insert and workpiece, and it hindrance the separate of chip, so, for this reason, MA make longer chip compared to other reinforced metals. NFC, MCA, and SA are medium average chip length La at high cutting speed compared to MA, but sample 6 is not perfect for high cutting speed because all types of reinforcement together damage the chips and decrease the length of it. Fig. 9 also showed La at a low cutting speed of 10 m/min. NFC becomes the first best one for average chip length is followed by all other reinforcements due to low cutting speed and low cutting temperature, but MA is not perfect for high and low cutting speeds cutting. Figs. 10 and 11 showed chip formation style shape during cutting speeds of 10 and 90 m/min, respectively, the Figures showed three forms of chips as known as spring, semi-circle, and helical. The spring shape known as continuous chip and the others were semi-circle and helical known as discontinuous chip. It was found from Figs. 10 and 11; reinforced metals can change the chip style from discontinuous chip to continuous chip but in limited quality and quantity of reinforced metals.
2.145 1.720 1.382 1.220 1.748 1.526
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
4775
Fig. 12 – A TYLOR-HOBSON (10) surface roughness device.
Fig. 13 – Effect of cutting speed on average surface roughness within different sample detail compositions.
MCA due to its structure and grain size of MA and SA. From the results are shown in Table 10, the maximum and minimum values of Ra are (4.906 m and 1.220 m) at 10 m/min and 90 m/min respectively. So the best improvement of Ra is at cutting speed of 90 m/min. These means high cutting speed and low feed rate produced a better surface finish which leads to increase the tool life.
5.
Conclusions
In this study, Al 6063 alloy based composite reinforced particles are fabricated using two steps of techniques of the stir casting process. Details of the experimental investigation are
presented for the effects of different types of metal matrix composites on mechanical properties, microstructural observation, average surface roughness, and chip shape formation style. The conclusions of the results in this investigation study can be summarized in the following points: 1. Aluminum alloy composites were successfully produced by liquid stir casting technique by adding ceramics, synthetic, and waste vegetable reinforcement in 6063 Al alloy to produced metal matrix composite. 2. The main properties of the MMCs are mainly depending on the microstructural parameters of the reinforcing materials type and volume fraction. Stir casting technique which is used in this paper produces compact grain boundary,
4776
3.
4.
5.
6.
7.
8.
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
smaller, stronger and uniform distribution grain size with good interface bonding of particulate matrix. The YTS and UTS, which obtained from the results of MMCs, are much more than Al 6063 alloy especially when adding all four types of composites together. The effect of NFC for increasing YTS and UTS is very less compared with other types of reinforced metal due to its chemical composition (Cr2 O3 ). The hardness of the MMCs is higher than Al 6063 alloy and the cast of ceramic additives MA composite increasing hardness more than the other types of MMCs due to the high atomic bonding between the atoms. Experimental results show that the impact strength increased by adding MA and SA reinforcements respectively, while, the less decrease of elongation was by NFC and MCA. All four types of additives will be given a high acceptable standard range of chip volume ratio. On the other hand, the chip length increases by NFC during cutting speed of 10 m/min, but within cutting speed of 90 m/min, MA has an important role to change the length and formation style of the chip from discontinuous chip to continuous chip. The machinability of MMCs is different from the traditional materials because of the presence of reinforcement particles, during turning operation the surface roughness is decreased by adding NFC and MCA especially when the velocity changed from10 m/min to 90 m/min, it means high velocity produced a better surface finish which leads to long tool life. The advent of the importance of new agricultural waste SA in particulate form as a reinforcement for MMCs is not just of added advantage to our manufacturing industries because of its availability and low cost, but it also reduces the rate of environmental pollution by converting such waste from agro processes into useful raw materials for engineering purposes.
Conflicts of interest The authors declare no conflicts of interest.
Acknowledgments This study was mainly supported by the Department of Mechanical & Mechatronics Engineering, College of Engineering, Salahaddin University-Erbil, Ministry of Higher Education and Scientific Research, Kurdistan Regional Government (KRG), Iraq.
references
[1] Venkatesulu M, Ramakotaiah K. Production and mechanical properties of Al 6063/B4C composites. J Mech Eng Res Dev 2019;42(1):46–9, http://dx.doi.org/10.26480/jmerd.01.2019.46.49. [2] Alkadir I, Salim L. Effect of B4 C/fly ash addition on wear and mechanical properties of Al-Cu-Mg alloy. Eng Technol J 2017;35(4):301–10.
[3] Aniban N, Pillai R, Pai B. An analysis of impeller parameters for aluminum metal matrix composites synthesis. Mater Des 2002;23(1):553–6, http://dx.doi.org/10.1016/S0261-3069(02)00024-9. [4] Tzamtzis S, Barker N, Babu N, Patel J, Dhindaw B, Fan Z. Processing of advanced Al/SiC particulate metal matrix composites under intensive shearing–A novel rheo-process. Composite Appl Sci Manufacturing 2009;40(1):144–51, http://dx.doi.org/10.1016/j.compositesa.2008.10.017. [5] Canakci A, Ozashin S, Varol T. Prediction of effect of reinforcement size and volume fraction on the abrasive wear behavior of AA2014/B4 Cp MMCs using artificial neural network. Arab J Sci Eng 2014;39(8):6351–61, http://dx.doi.org/10.1007/s13369-014-1157-9. [6] George P, Kantharaj I, Mohanasundaram S, Rao G. Experimental investigation on the mechanical properties of LM6 aluminum alloy reinforced with boron carbide and titanium hybrid composites. Int J Mech Eng Technol 2019;10(2):1584–93. [7] Kathiresan M, Theerkkatharisanan R, Rajan A. Optimization of hybrid aluminum metal matrix composite through taguchi method. Int Res J Eng Technol 2017;4(3):569–74. [8] Lakshmipathy J, Kulendran B. Reciprocating wear behavior of 7075Al/SiC and 6061Al/Al2O3 composites: a study of effect of reinforcement, stroke and load. Tribol Ind 2014;36(2):117–26. [9] Bhadare R, Sonawane P. Preparation of aluminum matrix composite by using stir casting method. Int J Eng Adv Technol 2013;3(2):61–5. [10] Ashofteh A, Mashhadi M, Amadeh A. Thermal shock behavior of mixed composite top coat APS TBCs. Ceramics–Silikáty 2018;62(2):200–9, http://dx.doi.org/10.13168/cs.2018.0013. [11] Sozhamannan G, Balasivanandh S, Venkatagalapathy V. Effect of processing parameters on metal matrix composites: stir casting process. J Surf Eng Mater Adv Technol 2012;2(1):11–5, http://dx.doi.org/10.4236/jsemat.2012.21002. [12] Kumar A, Lal S, Kumar S. Fabrication and characterization of A359/Al2O3 metal matrix composite using electromagnetic stir casting method. J Mater Res Technol 2013;2(3):250–4, http://dx.doi.org/10.1016/j.jmrt.2013.03.015. [13] Alaneme K, Bodunrin M. Mechanical behavior of alumina reinforced AA6063 metal matrix composites developed by two step-stir casting process. ATCA Technica Corviniensis-Bull Eng 2013:105–10. ROMANIA. [14] Patel V, Goyal B, Shah C. Optimization of process parameters of CNC milling for aluminum metal matrix composite. Int Conf Multidiscip Res Pract 2014;1(8):394–9. INDIA. [15] Malaki M, Xu W, Kasar A, Menezes P, Diertinga H, Varma R, et al. Advanced metal matrix nanocomposites. Metals 2019;9(330), http://dx.doi.org/10.3390/met 9030330. [16] Bodunrin M, Alaneme K, Chown L. Aluminum matrix hybrid composites: a review of reinforcement philosophies; mechanical, corrosion and tribological characteristics. J Mater Res Technol 2015;4(4):434–45, http://dx.doi.org/10.1016/j.jmrt.2015.05.003. [17] Sood P, Sehgal R, Dwivedi K. Machinability of hypereutectic cast Al-Si alloys processed by SSM processing technique. Indian Acad Sci 2017;42(3):365–78, http://dx.doi.org/10.1007/s12046-017-0609-9. [18] Hindi J, Kini U, Sharma S, Gurumurthy B, Shankar M. Mechanical characterization of stir cast Al 6063 matrix SiC reinforced metal matrix composite. In: 5th International Conference on Automotive, Mechanical and Materials Engineering. 2015. p. 69–73. [19] Phanibhubshana V, Chandrappa C, Niranjan H. Evaluation of mechanical properties of Al 6061 reinforced with hematite. J Multidiscip Eng Sci Technol 2015;2(1):255–60. [20] Alaneme K, Bodunrin M, Awe A. Microstructure, mechanical and fracture properties of groundnut shell ash and silicon
j m a t e r r e s t e c h n o l . 2 0 1 9;8(5):4766–4777
carbide dispersion strengthened aluminum matrix composites. J King Saud Univ Eng Sci 2016;1(1):1–8, http://dx.doi.org/10.1016/j.jksues.2016.01.001. [21] Haider K, Alam M, Redhewal A, Saxena V. Investigation of mechanical properties of aluminum based metal matrix composites reinforced with SiC and Al2 O3 . Int J Eng Res Technol 2015;5(9):63–9. [22] Raju S, Rao G, Rao M. Optimization of machinability properties on aluminum metal matrix composites prepared
4777
by in-situ ceramic mixture using coconut shell ash-taguchi approach. Int J Conceptions Mech Civil Eng 2015;3(2):17–21. [23] Joseph O, Babarmu K. Agricultural waste as a reinforcement particulate for aluminum metal matrix composites (AMMCs): a review. Fibers 2019;7(33):1–9, http://dx.doi.org/10.3390/fib7040033. [24] Grote K, Antonsson E. Springer handbook of mechanical engineering. In: Springer Handbooks; 2009. p. 611–2. XXVII.