Effect of Al2O3 particles on mechanical and tribological properties of Al–Mg dual-matrix nanocomposites

Journal Pre-proof Effect of Al2O3 particles on mechanical and tribological properties of Al–Mg dualmatrix nanocomposites M.A. Eltaher, A.Wagih, A. Melaibari, A. Fathy, G. Lubineau PII:

S0272-8842(19)33206-7

DOI:

https://doi.org/10.1016/j.ceramint.2019.11.028

Reference:

CERI 23397

To appear in:

Ceramics International

Received Date: 23 September 2019 Revised Date:

2 November 2019

Accepted Date: 4 November 2019

Please cite this article as: M.A. Eltaher, A.Wagih, A. Melaibari, A. Fathy, G. Lubineau, Effect of Al2O3 particles on mechanical and tribological properties of Al–Mg dual-matrix nanocomposites, Ceramics International (2019), doi: https://doi.org/10.1016/j.ceramint.2019.11.028. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Ltd.

Effect of Al2O3 Particles on Mechanical and Tribological Properties of AlMg dual-matrix Nanocomposites M.A. Eltahera,b,*, A.Wagihb,c, A. Melaibaria, A Fathyb, G. Lubineauc a

b

Mechanical Engineering Department, Faculty of Engineering, King Abdulaziz University (KAU), P.O. Box 80204, Jeddah, Saudi Arabia

Mechanical Design and Production Dept., Faculty of Engineering, Zagazig University, P.O. Box 44519, Zagazig, Egypt c

King Abdullah University of Science and Technology, Physical Science and Engineering Division (PSE), COHMAS Laboratory, Thuwal 23955-6900, Saudi Arabia *Corresponding author: M.A. Eltaher ([email protected])

Abstract This article aims to manufacture homogenous dual-matrix Al-Mg/Al2O3 nanocomposite from their raw materials and give insight into the correlation between powder morphology, crystallite structure and their mechanical and tribological properties. Al-Mg dual-matrix reinforced with micro/nano Al2O3 particles was manufactured by a novel double high-energy ball milling process followed by a cold consolidation and sintering. Microstructure and phase composition of the prepared samples were characterized using FE-SEM, EDS and XRD inspections. Mechanical and wear properties were characterized using compression and sliding wear tests. The results showed that a milling of Mg with Al2O3 particles in an initial step before mixing with Al has the beneficial of well dispersion of Al2O3 nanoparticles in Al-Mg dual matrix. The Al-Mg dual matrix reinforced with nano-size Al2O3 showed 3.29-times smaller crystallite size than pure Al. Moreover, the hardness and compressive strength are enhanced by adding nano-size Al2O3 with Al-Mg dual matrix composite while the ductility is maintained relatively high. Additionally, the wear rate of this composite was reduced by a factor of 2.7 compared to pure Al. The reduced crystallite size, the dispersion of Al2O3 nanoparticles and the formation of (Al-Mg)ss were the main improvement factors for mechanical and wear properties. Keywords: Al-Mg Dual Composite; Microstructure; Mechanical Properties; Tribological Properties.

1

1. Introduction Aluminum alloys and their composites have revealed superior performance compared to their rival metals. The selection of these materials derives from one important attribute of aluminum metal—lightweight. Owing to their low weight-density, they are used to reduce fuel consumption by reducing weight of transport machine/structure such as motorcycle, cars, trucks, trains, spacecraft and aeronautics [1]. In manufacturing of MMCs, the appropriate selection of their reinforcements either metallic or ceramic is considerably essential to enhance mechanical properties and wear resistance [1-3]. Recently, Al-based MMCs received lots of attention from researchers and designers, because of their applicability in numerous advanced applications. Kondoh et al. [4] studied mechanical and microstructural behaviors of Al–Mg–Si alloy composites strengthened by multi-walled carbon nanotubes (MWCNTs). Mosleh-Shirazi et al. [5] illustrated improvement of corrosion of Al-MMCs reinforced by SiC nanoparticle. Faisal and Kumar [6] investigated effects of addition of SiC nanoparticles on the mechanical and tribological behavior of Al-MMCs. Sadeghi et al. [7] investigated microstructure behaviors of Al-MMCs reinforced by Al2O3 nanoparticles produced by spark plasma sintered process. Among all reinforcement ceramics, Al2O3 were widely used to reinforce Al matrix, due to their superior properties [8, 9]. Focusing down on Al-based MMCs reinforced with Al2O3 particles, Fathy et al. [10] and Wagih et al. [11] enhanced mechanical and wear properties of hybrid Al-Al2O3 composite coated by Ni and graphene nanoplatelets (GNPs). Abbass and Sultan [12] studied impacts of Al2O3 nanoparticles on corrosion of Al-base alloy (AlCu-Mg). Asiri et al. [13] investigated theoretically elastoplastic behaviors of Al-Al2O3 nanocomposites through loading and unloading indentation process. Awotunde et al. [14] presented inspiration of sintering techniques on mechanical properties of Al-nanocomposites reinforced by Al2O3 and carbonaceous compounds. Chao et al. [15] obtained Al-matrix composites with a good strength and ductility at high temperature by adding Al3Ti and Al2O3 nanoparticles as reinforcement. 2

Kumar et al. [16] presented the impact of Al alloys nanocomposite reinforced by Al2O3 and MWCNTs on their tribological properties. Tosun and Kurt [17] exploited powder metallurgy to fabricate Al-Mg MMCs reinforced with micro-sized SiC and Al2O3 particles. Suresh et al. [18] studied mechanical and wear properties of hybrid composites with Al matrix reinforced by Al2O3 and SiC in nanosize and Mg in microsize. In general, wettability between metals and ceramic reinforcements is a key factor for achieving MMCs with improved properties especially for nanosized reinforcements [19]. Serval studies have been performed to improve the wettability between matrix and reinforcement by electroless coating of reinforcement particles with Ti, Ag, Co and Ni [9, 10, 20, 21]. Since this technique is based on the deposition of the metals on the ceramic particles surface, it has been proved that an improvement of wettability occurs between reinforcement and metal matrix for relatively coarse particles [20]. However, for nanoparticles reinforcement with nanosize surface area, the applicability of this technique is limited. Even though this technique is effectiveness, it is not applicable for all metals and always requires a deposition of intermediate metal layer with good electric conductivity to prepare the ceramic particles for electroless coating process [10, 11]. Currently, mechanical alloying ball milling and casting are the most effective techniques to manufacture MMCs [8]. Gubicza et al. [22] examined impacts of Mg content and milling time on microstructure, hardness and mechanical properties of Al-rich Al–Mg solid solutions. Crivello et al. [23] estimated the limited homogeneity range of the Mg-Al -phase produced by HEBM. Saberi et al. [24] and Zawrah et al. [25] proved that increasing in time of milling tends to decrease grains size unlike the lattice strain of Al matrix reinforced by SiC. Akbari et al. [8] and Mobasherpour et al. [26] fabricated Al-Al2O3 MMCs by using HEBM to avoid agglomeration of nanoparticles in matrix. Bastwros et al. [27] investigated the effect of HEBM on graphene reinforced aluminum composite fabricated by semi-solid sintering.

3

With the aim of improving wettability between Al and Al2O3 nanoparticles, a novel manufacturing methodology is presented in the current manuscript by addition of Mg particles, which have excellent solubility in Al matrix [28-30]. Therefore, the idea of the proposed manufacturing process is to use Mg particle as a carrier for Al2O3 nanoparticle before mixing with Al. To achieve this objective, Al-Mg dual matrix reinforced with Al2O3 nano/micro-particles is manufactured using double-HEBM process. First, Mg particles are milled with Al2O3 nanoparticles for 5 h until achieving good dispersion of the mixture. Then, the obtained Mg-Al2O3 mixture is milled with Al matrix for 15 h to manufacture Al-Mg dual matrix nanocomposite. Following this procedure, Al2O3 nanoparticles which was stacked to Mg particles during the first HEBM process are embedded in the formed Al-mg solid solution achieving good wettability between Al2O3 and Al particles. The structural, mechanical and wear properties of the produced samples are characterized highlighting the influence of reinforcement particle size and Mg addition on the properties of the produced nanocomposites. 2. Material and Experiments Pure aluminum (Al), magnesium (Mg) powders (40 µm particle size and 99.5 wt.% purity) and alumina (Al2O3) powder (50 µm and 300 nm particle size and 99.9 wt.% purity) are exploited as raw materials to manufacture Al-10%Mg/5%Al2O3 nanocomposites. The produced samples are labeled here as follows: (A-n) for Al/5%nano Al2O3, (A-M-n) for Al-10%Mg-5%nano Al2O3 and (A-M-m) for Al-10%Mg-5%micron Al2O3. Double-HEBM is used for preparation of A-M-m and A-M-n composites while a conventional HEBM is applied for production of A-n composites. For doubleHEBM process, first, Mg and Al2O3 particles are mixed in a planetary ball milling machine for 5 h. During this stage, Al2O3 is stacked over the plastically deformed Mg particles which helps for better dispersion of Al2O3 in Al matrix [31, 32]. Then, the Mg-Al2O3 mixture is ball milled with Al for 15 h to produce Al-10%Mg/5%Al2O3 nanocomposites. However, for A-n composites, Al2O3 and Al are ball milled for 20 h. The milling parameters, used through milling process, are ball to powder ratio = 4

10:1, ball size = 10 mm (decided based on previous investigations by the authors [33]) and milling sped = 250 rpm. Balls are made of 100 Cr6 hardened steel to avoid corrosion during milling. Stearic acid (3 wt.%) is added to the mixture as a process control agent to reduce the Al powder stacking during milling. After the second milling step, the powders are consolidated using in a cylindrical die of 10 mm height and height to diameter ratio = 1 under 700 MPa using hydraulic press. Prior to compaction step, 5 g of each powder sample is separated and stored in vacuum for powder morphology and crystallite structure inspections. While for the rest of the powder, paraffin wax (0.5 wt.%) is added to reduce friction with the die walls during compaction. Finally, sintering process is applied to all the compacted samples using tuber furnace in hydrogen atmosphere at 550 °C for 2 h. 10 °C/min and 2 °C/min heating and cooling rates are applied during the sintering process, respectively. Field Emission Scan Electron Microscope (FE-SEM) is used to check the morphological changes in the milled powders and the consolidated samples. While Energy Dissipative Spectrum (EDS) unit attached to the FE-SEM is used to check the elemental composition of the produced samples. The average powder particle size is calculated based on the obtained FE-SEM powder inspections using Image-J software. X-Ray diffraction (XRD) technique is used to check the crystallite structure of the milled powder with inspection range 2 = 10 − 80° with 0.02° step size. William-Hall equation [34-36] is applied to compute the crystallite size of the milled powders using the peak profiles of the obtained XRD data: ∆

−

.

=

where 2∆ is the full width at half maximum,

(1) is the crystallite size,

= 0.154

is the X-Ray

wavelength and is the peak position. Densification parameters of sintered samples in terms of apparent porosity and bulk density are

5

measured in an aqueous media by Archimedes principle, using water as a floating liquid according to JIS R2205-1992. Following the ASTM E9-89a standard recommendation, compression test is performed using universal testing machine with 500 KN load capacity. Samples for this test have cylindrical shape with 10 mm height and 1:1 height to diameter ratio. The crosshead speed of the machine is kept 2 mm/min. Three specimens are tested for each batch. Microhardness test is performed using Vickers test to measure microhardness according to ASTM-E92 standard. 50 g load is applied to the indenter with 10 s dwell time. At least ten indentations are performed for each sample in arbitrary positions and the average value is reported. Tribological properties of the manufactured dual-matrix nanocomposites are characterized using pin-on-disc wear experiment in dry conditions. The manufactured samples are machined to meet the required pin size of this experiment (φ 9mm×7mm). The disc is made of hardened steel with hardness 60 HRC and surface roughness of 53 µm. In order to highlight the influence of sliding wear test parameters on the tribological response of these nanocomposites, three sliding speeds 0.4, 0.7 and 1 m/min are considered, and four different testing loads 3, 6, 9 and 12 N are applied. The rotational speed and sliding distance are kept constant at 300 rpm and 200 m, respectively. After wear experiment the pin is weighed using an electronic balance. Weight loss, which is the difference between the sample weight before and after testing, is considered as the wear rate. 3. Results and discussion 3.1 Micro/nano-structure and phase identification Fig. 1 illustrates morphology of A-n, A-M-m and A-M-n composite powders after ball milling. Fig. 1(a) presents that the A-n composite powder have an irregular shape with sharp edges and average particle size around 25. 3 µm, which highlights that Al particle size is reduced by 36.75 % due to ball milling. During HEBM process, welding and fracture of ductile particles are dominated

6

through the process. During the beginning of the milling, welding between Al particles is the dominant mechanism due to high temperature generated from collision between balls, powder particles and container walls. Moreover, the higher ductility of Al particles can influence the formation of larger Al particles [36]. Due to cumulative collision of Al particles with balls in the same direction, particles are deformed perpendicularly to the collision direction forming flake-shape particles [10, 30, 37, 38]. Continuing the milling process, the flake-shaped particles are subjected to excess strains in the direction perpendicular to the collision direction, which leads to break of these flake particles. Reduction of the size of Al2O3 particles are observed and staked over Al particles due to the entrapping of these particles between Al particles during ball milling. The morphology of A-M-m powder composite after ball milling is shown in Fig. 1(b). The particles are observed with equiaxed spherical shape and almost equal particle size. The average particle size is 15.6 µm, achieving a reduction of average particle size by 61% compared to pure Al which demonstrates that the presence of Mg particles helps for particle size reduction. The cold working of Al particles occurred due to milling resulting in higher dislocation density which allows for better diffusion of Mg atom in Al atoms [22]. Additionally, the high temperature raised at the interface between Al and Mg atoms due to collision helps for diffusion of Mg atoms. These two effects allow the formation of (Al-Mg)ss solid solution on the nanocrystalline grains which reduce the ability of the grains to plastically deforms [30]. Consequently, the tendency of particles to fracture is larger than its tendency to deform and hence large particle size reduction occurs. The particles of the A-M-n composite have spherical shape with 11.5 µm average particle size as shown in Fig. 1(c), achieving 71.25% particles size reduction compared to pure Al. The reinforcement particle size is affecting on the matrix particle size through ball milling. The addition of nanoparticles accelerates the fracture process of Al particles during milling, due to entrapping of these nanoparticles between Al particles during collision, causing strain hardening of Al particles and reducing their ductility. Fig. 1(d) demonstrates a higher magnification of A-M-n nanocomposite powder. As shown, Al2O3 7

nanoparticles are precipitated on Al particles. The size of several Al2O3 particles, shown in the figure, proves the reduction of Al2O3 particle size to ~150 nm compared to 300 nm for the as received powders. Fig. 1(e) shows EDS analysis of a selected particle, showing the composition of the measured particles, Al and O only, and proving that these particles are Al2O3 nanoparticles. In all the prepared composites, no agglomeration of Al2O3 nanoparticles is observed. To ensure the distribution of the three phases, a mapping analysis of A-M-n composite is shown in Fig. 2. The figure illustrates the excellent distribution of the three phases in the powder sample. Fig. 3 presents XRD results of A-n, A-M-m and A-M-n composite powders after ball milling. The figure shows the presence of three phases Al, Al2O3 and (Al-Mg)ss which indicates that the prepared composites are free from any contaminates. There is no evidence on presence of Mg peaks which indicates that all the Mg added is dissolved in Al forming the FCC supersaturated solid solution (Al-Mg)ss. It is observed in the inset figure that a shift to lower angle occurred in A-M-m and A-M-n composites due to the dissolution of Mg large atoms in Al nanocrystalline structure. Therefore, it is demonstrated that the structure of the prepared composites is free of Mg particles and intermetallic phases between Al and Mg and a complete dissolution of Mg atoms in Al matrix forming the super saturated solid solution (Al-Mg)ss. These results are reasonable since available studies in the literature have shown that a complete solid solution of Mg in Al can be achieved up to 30% Mg concentration [29, 23, 31, 39]. The height of Al2O3 peaks is shorter compared to Al due to its lower content. Al peaks are broadening in A-M-m and A-M-n composite powders due to the reduction of crystallite size and the break of Al particles during ball milling. Thus, it is worth highlighting that the collision between particles and balls affects the crystallite structure of the particles as well as their morphology. Grains elongate in the direction perpendicular to the collision direction when they are subjected to repeated impacts at the same side resulting in crystal structure refinement [25, 26].

8

The crystallite size is computed using Eq. (1) equal to 55.4, 42.5 and 31.9 nm for A-n, A-M-m and A-M-n nanocomposite powders compared to 105 nm for pure Al. The crystallite size of A-n composite is reduced by 1.9 compared to pure Al due to the presence of Al2O3 nanoparticles that generate crystal defects and dislocations in Al structure [19, 24, 40]. Additionally, the ball milling process can influence on the crystallite size by generation of dislocations during formation of subgrains [41]. The crystallite size is smaller for A-M-m and A-M-n nanocomposite powders achieving reduction of 2.47- and 3.29-times compared to pure Al due to the addition of Mg particles. The formation of (Al-Mg)ss solid solution during ball milling and its precipitation on the grain boundaries of Al grains activate the generation of more dislocations and crystal defects such as point defects [10, 22, 30]. Interestingly, comparing the crystallite size of A-M-m and A-M-n nanocomposite powders, it is observed that, the crystallite size of the composite containing nano Al2O3 particles is smaller than the other. This is due to the ability of these nanoparticles to penetrate the ultrafine grain structure of Al causing stacking faults in the lamellar structure such as twining and point defects [2, 42]. Fig. 4 shows the microstructure of A-n, A-M-m and A-M-n nanocomposite after consolidation. Voids are observed in the three manufactured composites. The presence of voids in such composites is common due to the entrapping of air during compaction and the presence of nanoceramic phase which reduces the diffusion of metals during sintering [10, 11]. The percentage of voids in A-n composite with larger size compared to A-M-m and A-M-n composites. This is due to the irregular shape of particles with the sharp edges observed for A-n composite (see Fig. 1(a)). The percentage of voids is reduced in samples contain Mg due to the formation of the supersaturated solid solution which fill in the gabs between grains and hence more dense material is consolidated as shown in Fig. 5. The composition of a random area in the structure of A-M-n composite is shown in Fig. 4(d) which highlights that any point in the sample contains three elements, Al, Mg and O only. Additionally, the distribution of the three elements in A-M-n nanocomposite after consolidation is 9

shown in Fig. 6, highlighting the excellent distribution of three elements inside the matrix which proves the homogeneous distribution of Al2O3 nanoparticles and Mg in Al matrix. 3.2 Mechanical Properties The microhardness of A-n, A-M-m and A-M-n nanocomposites is shown in Fig.7. Generally, all prepared nanocomposites show larger hardness than pure Al due to the grain refinement caused by ball milling and presence of Al2O3 nanoparticles which possess higher hardness than Al. The hardness of A-n and A-M-m nanocomposites is almost equal. However, A-M-n nanocomposite shows improved hardness by 1.8 compare to pure Al and by 1.3 compared to A-n composite. This improvement achieved due to the addition of Mg particles which result to formation of (Al-Mg)ss solid solution, the reduction of crystallite size and consequently grain size (see Fig. 4(e)). It is well known that, the strength of grain boundaries is smaller than the grain core due to the random distribution of atoms in grain boundary, which is not the case of the grain, well distributed [14]. The formation (Al-Mg)ss and its precipitation on the grain boundaries increases the strength of grain boundaries, hence, resulting a global strength improvement [43]. The compressive strength and strain of the prepared samples are shown in Fig. 8. Almost the same trend observed for microhardness, can be observed for the compressive strength. A-M-n nanocomposite shows the largest compressive strength among the inspected samples with improvement of 1.76, 1.21 and 1.14 compared to pure Al, A-n and A-M-n composites, respectively. This larger improvement achieved for A-M-n nanocomposite is attributed to the crystallite/grain size reduction and the formation of solid solution between Al and Mg. As previously stated, the crystallite size of these composite is 31.9 nm compared to 105 nm for pure Al achieving a reduction with a factor of 3.29. The presence of (Al-Mg)ss and Al2O3 nanoparticles in the grain boundaries strengthen the grain boundaries which have higher intensity in this composite compared to the other composites due to the lower grain size (see Fig.4(e)). The A-M-n composites shows an important

10

advantage over the other composites which is the higher strain at failure as shown in Fig. 8(b). This composite shows 0.242% failure strain compared to 0.166% and 0.206% for A-n and A-M-m composites. This higher stain is attributed to the ability of Al grains to slip or rotate during deformation [43, 44]. The presence of the solid solution on the grain boundaries increase the tendency of grains to rotate corresponding to each other and hence higher strain is attained. 3.3 Tribological Properties The wear rate for pure Al, A-n, A-M-m and A-M-n composites nanocomposites tested at different load is shown in Fig.9. Almost linear increase of wear rate with the test load following Archard’s law [45], the penetration of the pin in the sample increases a higher material removal during sliding. These results agree well with available results in the literature [46], indicating that the wear behavior is analogues to the indentation response. Therefore, the test load shows similar influence on all the tested composites. The A-M-n composites shows the lower wear rate among the tested composites. For example, at 12 N normal load, A-M-n composite shows 1.36 ×10-3 g/m wear rate while pure Al, A-n and A-M-m composites show 3.65 ×10-3, 2.62 ×10-3 and 1.61 ×10-3 g/m wear rate. This improved wear resistance is attributed to fine grained structure of A-M-n nanocomposite as shown in Fig. 4. Moreover, the higher strength and hardness of this composite contribute the improvement of the wear rate due to the increase of indenter penetration impedance. Additionally, the formation of the solid solution reduces plastic deformation of the subsequent layers during sliding, which reduces the material removal rate and wear rate. To investigate the effect of Mg addition and Al2O3 particle size on the wear response of AlMg/Al2O3 duel-matrix nanocomposite, worn surfaces of pure Al, A-n, A-M-m and A-M-n nanocomposite samples are inspected using FE-SEM, as shown in Fig. 10. Although the test load is equal, larger grooves (width and depth) are observed for pure Al compare to the manufactured 11

nanocomposites. These larger grooves are generated because for Al samples, delaminations are the main wear mechanism due to the separation of coarse debris in form of layers. The separation of coarse debris occurred due to the lower hardness of Al compared to other samples which allow deep penetration of the indenter during wear test [47]. The removal of coarse debris causing scratch and galling in the sample surface parallel to the sliding direction which creates thin deformed sheets [48]. Hence, the larger debris in this case acts as a secondary material removal source resulting in higher wear rates. Moreover, the wear stresses due to siding increases with increasing sliding contact time resulting in deformation of the contact surface forming thin-layer with higher strains and temperatures. Further sliding accumulates strains at these thin-layers, resulting in their separation which causes the wear delamination mechanism as shown in Fig. 10(a). For A-n nanocomposite, the wear worn surface is different than Al showing soft grooves and micro-cracks with lower intensity of delaminations. Since the wear test can be expressed as a special case of indentation test [13,49-51], the larger hardness of A-n nanocomposite (see Fig.7) reduces the penetration depth of the indenter on the surface which results in fine debris during sliding. Additionally, the presence of Al2O3 nanoparticles impedes the indenter movement during sliding contact between the surface and the indenter. The worn surface of A-M-m and A-M-n samples are shown in Fig. 10(c) and (d) indicating a delamination-free microstructure. Only microcracks are observed in both composites. The smaller crystallite size of these composites compared to Al and A-n nanocomposites improves the strength and the impedance of the surface for scratches. Additionally, the formation of (Al-Mg)ss over the grain boundaries improves the bonding between Al2O3 particles and Al grain interface which results in better penetration impedance of composite surface. These two reasons prevent the deformation on the sub-layers under the indenter and hence prevent the formation of delaminations during wear test and make the dominant wear mechanism is the microcracks at samples surfaces, which results in lower material removal and improves wear properties.

12

4. Conclusions Through this study, double High-Energy Ball Milling (HEBM) followed by consolidation and sintering are applied to manufacture Al-Mg/Al2O3 duel-matrix nanocomposites. Effects of Al2O3 particle size on mechanical and tribological properties of the prepared nanocomposites are investigated. The correlation between powder morphology, crystallite structure, and mechanical and tribological properties of Al-Mg/Al2O3 nanocomposites are presented and discussed. The most findings can be summarized as following: The double high-energy ball milling process is an efficient procedure to manufacture AlMg dual matrix reinforced with Al2O3 in micro and nanosize with homogeneous distribution of Al2O3 particles. In the first HEBM process, Mg particles, which have excellent solubility response in Al matrix, was used as a carrier for Al2O3 particles, which has low wettability with Al matrix, resulting in a better wettability of Al2O3 particles in Al matrix during the second HEBM process. Al-Mg dual-matrix reinforced with nano-size Al2O3 showed lower crystallite size than Al reinforced with nano-size Al2O3 and Al-Mg reinforced with micro size Al2O3 and due to the formation of (Al-Mg)ss solid solution and Al2O3 nanoparticles which facilitates the generation of crystal defects during second HEBM process. This dual-matrix nanocomposite showed an improvement of hardness and compressive strength with 94.2 % and 81.8%, compared to pure Al. Moreover, it showed relatively high compressive strain, 0.242 %, compared to 0.271%, 0.166% and 0.206% for pure Al, Al- Al2O3s and Al-Mg reinforced with micro-size Al2O3, respectively. Wear resistance of dual-matrix composite is improved with 62.4% compared with pure Al. The improvement is due to the presence of well dispersed Al2O3 nanoparticles, grain refinement and the formation of (Al-Mg)ss at the grain boundaries. 13

Acknowledgement This project was funded by the research and development office (RDO) at the minisitry of Education, Kingdom of Saudi Arabia. Grant no. (HIQI-28-2019). The authors also, aknowledge with thanks research and development office (RDO-KAU) at King Abdulaziz Unviesrty for techincal support. References [1] Nturanabo, F., Masu, L., & Kirabira, J. B. (2019). Novel Applications of Aluminium Metal Matrix Composites. In Aluminum Alloys and Composites. IntechOpen. [2] Gain, A. K., Zhang, L., & Quadir, M. Z. (2016). Composites matching the properties of human cortical bones: The design of porous titanium-zirconia (Ti-ZrO2) nanocomposites using polymethyl methacrylate powders. Materials Science and Engineering: A, 662, 258267. [3] Chawla, Krishan K. "Metal matrix composites." Materials Science and Technology (2006). [4] Kondoh, K., Fukuda, H., Umeda, J., Imai, H., & Fugetsu, B. (2014). Microstructural and mechanical behavior of multi-walled carbon nanotubes reinforced Al–Mg–Si alloy composites in aging treatment. Carbon, 72, 15-21. [5] Mosleh-Shirazi, S., Hua, G., Akhlaghi, F., Yan, X., & Li, D. (2015). Interfacial valence electron localization and the corrosion resistance of Al-SiC nanocomposite. Scientific reports, 5, 18154. [6] Faisal, N., & Kumar, K. (2018). Mechanical and tribological behaviour of nano scaled silicon carbide reinforced aluminium composites. Journal of Experimental Nanoscience, 13(sup1), S1-S13. [7] Sadeghi, B., Shamanian, M., Ashrafizadeh, F., Cavaliere, P., Sanayei, M., & Szpunar, J. A. (2018). Microstructural behaviour of spark plasma sintered composites containing bimodal micro-and nano-sized Al2O3 particles. Powder Metallurgy, 61(1), 50-63.

14

[8] Akbari, M. K., Baharvandi, H. R., & Mirzaee, O. (2013). Fabrication of nano-sized Al2O3 reinforced casting aluminum composite focusing on preparation process of reinforcement powders and evaluation of its properties. Composites Part B: Engineering, 55, 426-432. [9] Barakat, W. S., Wagih, A., Elkady, O. A., Abu-Oqail, A., Fathy, A., & EL-Nikhaily, A. (2019). Effect of Al2O3 nanoparticles content and compaction temperature on properties of Al–Al2O3 coated Cu nanocomposites. Composites Part B: Engineering, 107140. [10] Fathy, A., Wagih, A., El-Hamid, M. A., & Hassan, A. A. (2014). The effect of Mg add on morphology and mechanical properties of Al–xMg/10 Al2O3 nanocomposite produced by mechanical alloying. Advanced Powder Technology, 25(4), 1345-1350. [11] Wagih, A., Abu-Oqail, A., & Fathy, A. (2019). Effect of GNPs content on thermal and mechanical properties of a novel hybrid Cu- Al2O3/GNPs coated Ag nanocomposite. Ceramics International, 45(1), 1115-1124. [12] Abbass, M. K., & Sultan, B. F. (2019). Effect of Al2O3 nanoparticles on corrosion behavior of aluminum alloy (Al-4.5wt%Cu-1.5wt%Mg) fabricated by powder metallurgy. Engineering Structures and Technologies, 11(1), 25-31. [13] Asiri, S., Wagih, A., & Eltaher, M. A. (2019). Predictive model for spherical indentation on elastoplastic nanocomposites: Loading and unloading behavior. Ceramics International, 45(3), 3088-3100. [14] Awotunde, M. A., Adegbenjo, A. O., Obadele, B. A., Okoro, M., Shongwe, B. M., & Olubambi, P. A. (2019). Influence of sintering methods on the mechanical properties of aluminium nanocomposites reinforced with carbonaceous compounds: A review. Journal of Materials Research and Technology. [15] Chao, Z. L., Zhang, L. C., Jiang, L. T., Qiao, J., Xu, Z. G., Chi, H. T., & Wu, G. H. (2019). Design, microstructure and high temperature properties of in-situ Al3Ti and nano- Al2O3

15

reinforced 2024Al matrix composites from Al-TiO2 system. Journal of Alloys and Compounds, 775, 290-297. [16] Kumar, H. P., Joel, J., & Xavior, M. A. (2019). Effect of Reinforcement Surface Area on Tribological Behavior of Aluminum Alloy Nanocomposites. Procedia Manufacturing, 30, 224-230. [17] Tosun, G., & Kurt, M. (2019). The porosity, microstructure, and hardness of Al-Mg composites reinforced with micro particle SiC/ Al2O3 produced using powder metallurgy. Composites Part B: Engineering, 106965. [18] Suresh, S., Gowd, G. H., & Kumar, M. D. (2019). Mechanical and wear behavior of Al 7075/ Al2O3/SiC/mg metal matrix nanocomposite by liquid state process. Advanced Composites and Hybrid Materials, 1-10. [19] Wagih, A. (2016). Synthesis of nanocrystalline Al2O3 reinforced Al nanocomposites by highenergy mechanical alloying: microstructural evolution and mechanical properties. Transactions of the Indian Institute of Metals, 69(4), 851-857. [20] Khosroshahi, N. B., Khosroshahi, R. A., Mousavian, R. T., & Brabazon, D. (2014). Effect of electroless coating parameters and ceramic particle size on fabrication of a uniform Ni–P coating on SiC particles. Ceramics International, 40(8), 12149-12159. [21] Abu-Oqail, A., Samir, A., Essa, A. R. S., Wagih, A., & Fathy, A. (2019). Effect of GNPs coated

Ag on

microstructure and

mechanical

properties

of Cu-Fe dual-matrix

nanocomposite. Journal of Alloys and Compounds, 781, 64-74. [22] Gubicza, J., Kassem, M., Ribárik, G., & Ungár, T. (2004). The microstructure of mechanically alloyed Al–Mg determined by X-ray diffraction peak profile analysis. Materials Science and Engineering: A, 372(1-2), 115-122. [23] Crivello, J. C., Nobuki, T., & Kuji, T. (2007). Limits of the Mg–Al γ-phase range by ballmilling. Intermetallics, 15(11), 1432-1437.

16

[24] Saberi, Y., Zebarjad, S. M., & Akbari, G. H. (2009). On the role of nano-size SiC on lattice strain and grain size of Al/SiC nanocomposite. Journal of alloys and compounds, 484(1-2), 637-640. [25] Zawrah, M. F., Zayed, H. A., Essawy, R. A., Nassar, A. H., & Taha, M. A. (2013). Preparation by mechanical alloying, characterization and sintering of Cu–20 wt.% Al2O3 nanocomposites. Materials & Design, 46, 485-490. [26] Mobasherpour, I., Tofigh, A. A., & Ebrahimi, M. (2013). Effect of nano-size Al2O3 reinforcement on the mechanical behavior of synthesis 7075 aluminum alloy composites by mechanical alloying. Materials chemistry and physics, 138(2-3), 535-541. [27] Bastwros, M., Kim, G. Y., Zhu, C., Zhang, K., Wang, S., Tang, X., & Wang, X. (2014). Effect of ball milling on graphene reinforced Al6061 composite fabricated by semi-solid sintering. Composites Part B: Engineering, 60, 111-118. [28] Al-Aqeeli, N., Mendoza-Suarez, G., Labrie, A., & Drew, R. A. L. (2005). Phase evolution of Mg–Al–Zr nanophase alloys prepared by mechanical alloying. Journal of alloys and compounds, 400(1-2), 96-99. [29] Singh, D., Suryanarayana, C., Mertus, L., & Chen, R. H. (2003). Extended homogeneity range of intermetallic phases in mechanically alloyed Mg–Al alloys. Intermetallics, 11(4), 373-376. [30] Wagih, A. (2015). Mechanical properties of Al–Mg/ Al2O3 nanocomposite powder produced by mechanical alloying. Advanced Powder Technology, 26(1), 253-258. [31] Scudino, S., Sakaliyska, M., Surreddi, K. B., & Eckert, J. (2009). Mechanical alloying and milling of Al–Mg alloys. Journal of Alloys and Compounds, 483(1-2), 2-7. [32] Safari, J., Akbari, G. H., Shahbazkhan, A., & Chermahini, M. D. (2011). Microstructural and mechanical

properties

of

Al–Mg/Al2O3

nanocomposite

alloying. Journal of Alloys and Compounds, 509(39), 9419-9424.

17

prepared

by

mechanical

[33] Wagih, A., Fathy, A., & Kabeel, A. M. (2018). Optimum milling parameters for production of highly uniform metal-matrix nanocomposites with improved mechanical properties. Advanced Powder Technology, 29(10), 2527-2537. [34] Williamson, G. K., & Hall, W. H. (1953). X-ray line broadening from filed aluminium and wolfram. Acta metallurgica, 1(1), 22-31. [35] Curtze, S., Kuokkala, V. T., Oikari, A., Talonen, J., & Hänninen, H. (2011). Thermodynamic modeling of the stacking fault energy of austenitic steels. Acta Materialia, 59(3), 1068-1076. [36] Wagih, A., & Shaat, M. (2019). The dependence of accumulative roll bonded copper mechanical properties on grain sub-division, stacking faults, and lattice strains. Materials Science and Engineering: A, 756, 190-197. [37] Ostovan, F., Matori, K. A., Toozandehjani, M., Oskoueian, A., Yusoff, H. M., Yunus, R., & Ariff, A. H. M. (2015). Microstructural evaluation of ball-milled nano Al2O3 particulatereinforced aluminum matrix composite powders. International Journal of Materials Research, 106(6), 636-640. [38] Suryanarayana, C., & Al-Aqeeli, N. (2013). Mechanically alloyed nanocomposites. Progress in Materials Science, 58(4), 383-502. [39] Hamana, D., Baziz, L., & Bouchear, M. (2004). Kinetics and mechanism of formation and transformation of metastable β′-phase in Al–Mg alloys. Materials chemistry and physics, 84(1), 112-119. [40] Miraghaei, S., Abachi, P., Madaah-Hosseini, H. R., & Bahrami, A. (2008). Characterization of mechanically alloyed Fe100− xSix and Fe83. 5Si13. 5Nb3 nanocrystalline powders. Journal of materials processing technology, 203(1-3), 554-560. [41] Abu-Oqail, A., Wagih, A., Fathy, A., Elkady, O., & Kabeel, A. M. (2019). Effect of high energy ball milling on strengthening of Cu-ZrO2 nanocomposites. Ceramics International, 45(5), 5866-5875.

18

[42] Balogh, L., Ribárik, G., & Ungár, T. (2006). Stacking faults and twin boundaries in fcc crystals determined by x-ray diffraction profile analysis. Journal of applied physics, 100(2), 023512. [43] Höppel, H. W., May, J., & Göken, M. (2004). Enhanced strength and ductility in ultrafine‐ grained aluminum produced by accumulative roll bonding. Advanced engineering materials, 6(9), 781-784. [44] Wei, K. X., Wei, W., Wang, F., Du, Q. B., Alexandrov, I. V., & Hu, J. (2011). Microstructure, mechanical properties and electrical conductivity of industrial Cu–0.5% Cr alloy processed by severe plastic deformation. Materials Science and Engineering: A, 528(3), 1478-1484. [45] Archard, J. (1953). Contact and rubbing of flat surfaces. Journal of applied physics, 24(8), 981-988. [46] Fathy, A., Wagih, A., & Abu-Oqail, A. (2019). Effect of ZrO2 content on properties of CuZrO2 nanocomposites synthesized by optimized high energy ball milling. Ceramics International, 45(2), 2319-2329. [47] Krim, J. (2012). Friction and energy dissipation mechanisms in adsorbed molecules and molecularly thin films. Advances in Physics, 61(3), 155-323. [48] Sharma, N., Alam, S. N., Ray, B. C., Yadav, S., & Biswas, K. Wear behavior of silica and alumina-based nanocomposites reinforced with multi walled carbon nanotubes and graphene nanoplatelets. Wear, 418 (2019) 290-304. [49] Jahanmir, S., Suh, N. P., & Abrahamson Ii, E. P. The delamination theory of wear and the wear of a composite surface. Wear, 32(1) (1975) 33-49. [50] Wagih, A. Experimental and Finite Element Simulation of Nano-indentation on Metal Matrix Composites:

Hardness

Prediction. International

TRANSACTIONS A: Basics, 29(1) (2016) 78-86.

19

Journal

of

Engineering

(IJE),

[51] Wagih, A., & Fathy, A. Experimental investigation and FE simulation of nano-indentation on Al–Al2O3 nanocomposites. Advanced Powder Technology, 27(2) (2016) 403-410.

List of Figures Fig. 1. SEM micrograph of the prepared composite powders (a) A-n, (b) A-M-m, (c) A-M-n, (d) higher magnification of A-M-n and (e) EDS analysis of selected particle in the sample. Fig. 2. Mapping analysis of A-M-n composite powders showing the distribution of Al, Mg and O elements in the powder samples and their EDS analysis with the weight percent of each component. Fig.3. XRD patterns of A-n, A-M-m and A-M-n nanocomposites after ball milling. Fig. 4. SEM micrograph of the prepared composite after sintering (a) A-n, (b) A-M-m, (c) A-M-n and (d) EDS analysis of cross point in A-M-n composite.

Fig.5 Relative density of the prepared composites. Fig. 6 Mapping analysis of consolidated A-M-N nanocomposite after sintering. Fig. 7. Hardness of the prepared composites. Fig. 8. Compressive strength and strain of the prepared composites. Fig. 9. Variation of wear rate with the normal load for the prepared nanocomposites.

Fig. 10. SEM of worn surface for (a) pure Al, (b) A-n, (c) A-M-m and (d) A-M-n nanocomposites.

20

Fig. 1. SEM micrograph of the prepared composite powders (a) A-n, (b) A-M-m, (c) A-M-n, (d) higher magnification of A-M-n and (e) EDS analysis of selected particle in the sample.

21

Fig. 2. Mapping analysis of A-M-n composite powders showing the distribution of Al, Mg and O elements in the powder samples and their EDS analysis with the weight percent of each component.

22

Fig.3. XRD patterns of A-n, A-M-m and A-M-n nanocomposites after ball milling.

23

Fig. 4. SEM micrograph of the prepared composite after sintering (a) A-n, (b) A-M-m, (c) A-M-n and (d) EDS analysis of cross point in A-M-n composite.

24

Fig.5 Relative density of the prepared composites.

25

Fig. 6 Mapping analysis of consolidated A-M-N nanocomposite after sintering.

26

Fig. 7. Hardness of the prepared composites.

27

Compressive strengh [MPa]

450 400

a

350 300 250 200 150 100 50 0

Pure1 Al

2 A-n

3 A-M-m Composite

4 A-M-n

2 A-n

3 A-M-m Composite

4 A-M-n

0.35 0.3

b

Strain [%]

0.25 0.2 0.15 0.1 0.05 0

Pure1Al

Fig. 8. Compressive strength and strain of the prepared composites.

28

Fig. 9. Variation of wear rate with the normal load for the prepared nanocomposites.

29

a

Deep groove

b

Micro-cracks

Delamination Delamination

c

Soft groove

d

Micro-cracks

Micro-cracks

Fig. 10. SEM of worn surface for (a) pure Al, (b) A-n, (c) A-M-m and (d) A-M-n nanocomposites.

30

Declaration of interests ☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. ☐The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: