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To Study the Cooling Rate and Influence of Boron Carbide on Mechanical Properties of Aluminium LM13 Matrix B4C Reinforced Composites
Available online at www.sciencedirect.com
ScienceDirect Materials Today: Proceedings 4 (2017) 7202–7207
www.materialstoday.com/proceedings
ICAAMM-2016
To Study the Cooling Rate and Influence of Boron Carbide on Mechanical Properties of Aluminium LM13 Matrix B4C Reinforced Composites K.T. Akhila*, Jerry Varghesea, ArunRaphela, VinojKa, Frenosh K Francisa
a
Asst. Professor, Dept. of Mechanical Engineering, Viswajyothi College of Engineering and Technology, Kochi-686670-India,
Abstract Aluminium Metal Matrix Composites are one of the advanced engineering materials that have been widely used in aerospace and automotive industries due to their excellent mechanical properties. In Aluminium Metal Matrix Composite, aluminium matrix is strengthened by reinforcing it with hard ceramic particles like Sic, Al2O3, and B4C etc. Aluminium Metal Matrix Composite was manufactured by sand casting process with Aluminium-LM13 grade as base metal and boron carbide as reinforcement. This study investigates the cooling rate and influence of boron carbide on mechanical properties of Aluminium Metal Matrix Composites. Experiments were performed by casting of Aluminium Metal Matrix Composites with varying the weight Percentage of boron carbide from 3% to 9% and cooling rate is measured using k type thermocouple at point 1mm away from the mold cavity.In order to investigate the influence of boron carbide on mechanical properties microstructure analysis, tensile tests, hardness tests were conducted. Results showed that mechanical properties of Aluminium Metal Matrix Composite were improved with Percentage of boron carbide. © 2017 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility ofthe Committee Members of International Conference on Advancements in Aeromechanical Materials for Manufacturing (ICAAMM-2016). Keywords:Aluminium Metal Matrix Composites, Influence of boron carbide, Mechanical properties, Aluminium-LM13
1. Introduction Aluminium Metal Matrix Composites are widely used in automotive and aircraft industries because of their excellent mechanical properties [1, 2-3]. Increased use of Aluminium Metal Matrix Composite create a need for
* K.T. Akhila. Tel.:+91 9496285256. E-mail address:[email protected] 2214-7853© 2017 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility ofthe Committee Members of International Conference on Advancements in Aeromechanical Materials for Manufacturing (ICAAMM-2016).
K.T Akhil/ Materials Today: Proceedings 4 (2017) 7202–7207
7203
deep understanding of their mechanical properties. In this study Aluminium Metal Matrix Composites are manufactured by stir casting process with Aluminium-LM13 grade as base metal and boron carbide as reinforcement [1-3]. The aluminium matrix is getting strengthened when it is reinforced with the hard ceramic particles like Sic, Al2O3, and B4C etc. [4-5]. Composites were manufactured by varying the weight percentage of boron carbide as 3%, 6% and 9% so on. Reinforcement particles are the most important parameters influencing the mechanical properties of composites. A limited research work has been reported on Aluminium Metal Matrix Composites reinforced with B4C. Mostly used Reinforcement is SiC, because it is chemically compatible with aluminium and forms an adequate bond with the matrix without developing inter-metallic phase and has other advantages such as excellent thermal conductivity, high machinability, good workability and low cost [1,4-6]. This study investigates the influence of boron carbide on mechanical properties of Aluminium LM13 Matrix B4C Reinforced Composites. 2. Experimental Method and Testing Aluminium Metal Matrix Composite was manufactured by stir casting process with Aluminium-LM13 grade as base metal and boron carbide as reinforcement. LM 13 is an alloy of Al with Si, Cu, Mg etc. and it is suitable for very critical thermal parts. Boron Carbide has grain size of 33μ. It has good wear properties and Cost of this material is very high. It will give good interfacial bonding with the matrix alloy. Boron carbide is good reinforcement material for making composites, especially with aluminium. Particles distribution was found to be better in Al–B4C composites as compared to Al–SiC and Al–Alumina composites. Aluminium alloy LM13 is melted using Open Hearth Furnace. After some time preheated B4C particles are introduced into the furnace mixed up withmatrix and Stir it using iron rod. After mixing of both with matrix and reinforcement molten metal is poured in to sand moulds and allowed to cool and solidify, after some time cast specimens were with drawn from the moulds. Using a K-type thermocouple temperature at the sand mold 1mm away from the mould cavity is measured. Based on the measurement, cooling curves (temperature-time graph) were drawn and cooling rate is analysed with varying weight Percentage of boron carbide from 3% to 9%. Fig. 1 shows experimental setup for measuring temperature.
Fig. 1. Experimental setup for measuring temperature
In order to investigate the influence of boron carbide on mechanical properties of Aluminium Metal Matrix Composites, microstructure evaluation, hardness test and tensile test were conducted. Microstructure analysis is performed using an Inverted metallurgical microscope. Specimen is prepared by etching with diluted hydrofluoric acid after polishing on disc polisher. Microstructure was observed for 200xmagnification. Macro Hardness test was performed using Brinellhardness tester by applying a load of 1000N for 30 seconds .Test were repeated for 5 times in all specimens. Tensile Test is performed on Universal Tensile Testing equipment by setting a load of 10000N. Specimens were prepared to ASTM standard E8M with a gage length of 45mm and gage diameter of 9mm. Fig. 2. Shows specimen prepared for tensile test. Izod and Charpy Impact tests were performed using impact testing model IT13. Fig . 3. Shows specimen prepared for impact test and experiments were repeated five times.
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Fig. 2. Tensile testing specimen
Fig. 3. Impact testing specimen
3. Results and Discussion 3.1. Cooling rate and Microstructure evaluation Fig. 4.shows the changes in temperature with weight Percentage of boron carbide, and it is found that temperature initially increases then decreases after a period of time. Cooling rates are measured from the graph and found 30C/minute, 3.80C/minute and 4.60C/minute for for weight Percentage of boron carbide 3%, 6% and 9% respectively. Hence it can be inferred that increasing the weight Percentage of boron carbide lead to reduction of cooling rate or increase in solidification time.Fig. 5 shows the variation in microstructure (200X Magnification) with variation in reinforcement in Aluminium Metal Matrix Composites .The microstructure indicates the presence of B4C particles in the matrix. Whitish area is entirely representing base material aluminium matrix and remaining dark black particle area represents the reinforcement. Identification of the variation in microstructure, average grain size was measured using Metal Vision Software. Average grain size values were found to be 0.97 microns, 0.85 microns and 0.79 microns for weight Percentage of boron carbide 3%, 6% and 9% respectively. Microstructure is
K.T Akhil/ Materials Today: Proceedings 4 (2017) 7202–7207
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found fine in composite with high weight percentage of boron carbide and microstructure is observed coarse in composite with low weight percentage of boron carbide. Grain size is measured using metal vision software and found much higher in composite with low weight percentage of boron carbide compared to composite with high weight percentage of boron carbide. Mechanical properties were improved with reducing grain size [6-7].
Fig. 4. Cooling Curves of cast components with varying weight Percentage of boron carbide
(a)
(b)
(c)
Fig. 5. Variation in microstructure with varying weight Percentage of boron carbide (a) 3% (b) 6% (c) 9%
3.2. Hardness Test Evaluation Fig. 6 shows the hardness variation with variation in reinforcement in Aluminium Metal Matrix Composites. Hardness values were measured to be 84.4 BHV, 89.8 BHV, and 94.2 BHV for weight Percentage of boron carbide 3%, 6% and 9% respectively. Hardness was found increasing with increase with reinforcement boron carbide in Aluminium Metal Matrix Composites. This is due to increasing in particles in the matrix case an additional trigger to nucleation rate and causesa decrease in grain size which lead to increase in hardness [6-7].
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K.T Akhil/ Materials Today: Proceedings 4 (2017) 7202–7207
Fig. 6. Changes in hardness with weight Percentage of boron carbide
3.3. Tensile Test Evaluation Fig.7 shows the Ultimate tensile strength variation with variation in reinforcement in Aluminium Metal Matrix Composites. Ultimate Tensile stress values were measured to be 125.2 MPa, 135.6 MPa and 145.8 MPa for weight Percentage of boron carbide 3%, 6% and 9% respectively. Ultimate tensile strength were found increasing with increase with reinforcement boron carbide in Aluminium Metal Matrix Composites. This is due to grain refinement of composite with high reinforcement boron carbide.
Fig. 7. Changes in tensile strength with weight Percentage of boron carbide
3.4. Impact Test Evaluation Fig. 8 shows variation in impact strength with variation in weight Percentage of boron carbide for Charpy and Izod tests. Impact strength values for Charpy test was measured to be 54 kJ/m2, 58 kJ/m2 and 69 kJ/m2 for weight Percentage of boron carbide 3%, 6% and 9% respectively. For Izod test, values of 58 kJ/m2, 61 kJ/m2, and 72 kJ/m2 were measured above mentioned weight Percentage of boron carbide. Impact strength was found increases with increase with reinforcement boron carbide in Aluminium Metal Matrix Composites. This is due to grain refinement of composite with high reinforcement boron carbide.
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Fig. 8. Changes in impact strength with weight Percentage of boron carbide
4. Conclusion Cooling rate and Mechanical properties such as Hardness and Tensile strength of Aluminium Metal Matrix Composites were improved with Percentage of boron carbide. Hardness from 84.4 BHV to 94.2 BHV and Ultimate tensile strength from 125.2 MPa to 145.8 MPa and Impact strength from 70 kJ/m2 to 64 kJ/m2 were increased with increase in Percentage of boron carbide from 3% to 9% in LM13 matrix. This is due to fast nucleation rate cause grain refinement in composite with high reinforcement boron carbide. References [1]. GopalaKrishna. “Effect Of Boron Carbide Reinforcement On Aluminium Matrix Composites”, International Journal Of Metallurgical & Materials Science And Engineering(Ijmmse)”,3, 41-48. [2]. Toptan. “ Processing And Microstructure Characterization Of Aluminium alloy 1070 And Aluminium alloy 6063 Matrix B 4c P Reinforced Composites ”, Journal Of MaterialsAnd Design, 31, 513-519. [3]. Neelima Devi “Micro Structural Aspects of Aluminium Silicon Carbide Metal Matrix Composite”, Int. Journal of Applied Sciences and Engineering Research, 2, 48-54. [4]. Shorowordi “Microstructure And Interface Characteristics Of B4c, Sic And Al2O3 Reinforced Al Matrix Composites: A Comparative Study”, Journal Of MaterialsProcessing Technology, 142, 738-743. [5]. Cun-Zhu Nie “Production of Boron Carbide Reinforced 2024 Aluminium Matrix Composites by Mechanical Alloying “, Materials Transactions, 48, No. 5, 2007. 990 - 995. [6]. K.T. Akhil, Sanjivi Arul, R.Sellamuthu,”The effect of section size on cooling rate, microstructureand mechanical properties of A356 aluminium alloy in casting”, Procedia material science 5, 2014, 362-368. [7]. K.T. Akhil, Sanjivi Arul, R.Sellamuthu,”The Effect of Heat Treatment and Aging Process on Microstructure and Mechanical Properties of A356 Aluminium Alloy Sections in Casting”, Procedia engineering 97, 2014, 1676 – 1682.
ScienceDirect Materials Today: Proceedings 4 (2017) 7202–7207
www.materialstoday.com/proceedings
ICAAMM-2016
To Study the Cooling Rate and Influence of Boron Carbide on Mechanical Properties of Aluminium LM13 Matrix B4C Reinforced Composites K.T. Akhila*, Jerry Varghesea, ArunRaphela, VinojKa, Frenosh K Francisa
a
Asst. Professor, Dept. of Mechanical Engineering, Viswajyothi College of Engineering and Technology, Kochi-686670-India,
Abstract Aluminium Metal Matrix Composites are one of the advanced engineering materials that have been widely used in aerospace and automotive industries due to their excellent mechanical properties. In Aluminium Metal Matrix Composite, aluminium matrix is strengthened by reinforcing it with hard ceramic particles like Sic, Al2O3, and B4C etc. Aluminium Metal Matrix Composite was manufactured by sand casting process with Aluminium-LM13 grade as base metal and boron carbide as reinforcement. This study investigates the cooling rate and influence of boron carbide on mechanical properties of Aluminium Metal Matrix Composites. Experiments were performed by casting of Aluminium Metal Matrix Composites with varying the weight Percentage of boron carbide from 3% to 9% and cooling rate is measured using k type thermocouple at point 1mm away from the mold cavity.In order to investigate the influence of boron carbide on mechanical properties microstructure analysis, tensile tests, hardness tests were conducted. Results showed that mechanical properties of Aluminium Metal Matrix Composite were improved with Percentage of boron carbide. © 2017 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility ofthe Committee Members of International Conference on Advancements in Aeromechanical Materials for Manufacturing (ICAAMM-2016). Keywords:Aluminium Metal Matrix Composites, Influence of boron carbide, Mechanical properties, Aluminium-LM13
1. Introduction Aluminium Metal Matrix Composites are widely used in automotive and aircraft industries because of their excellent mechanical properties [1, 2-3]. Increased use of Aluminium Metal Matrix Composite create a need for
* K.T. Akhila. Tel.:+91 9496285256. E-mail address:[email protected] 2214-7853© 2017 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility ofthe Committee Members of International Conference on Advancements in Aeromechanical Materials for Manufacturing (ICAAMM-2016).
K.T Akhil/ Materials Today: Proceedings 4 (2017) 7202–7207
7203
deep understanding of their mechanical properties. In this study Aluminium Metal Matrix Composites are manufactured by stir casting process with Aluminium-LM13 grade as base metal and boron carbide as reinforcement [1-3]. The aluminium matrix is getting strengthened when it is reinforced with the hard ceramic particles like Sic, Al2O3, and B4C etc. [4-5]. Composites were manufactured by varying the weight percentage of boron carbide as 3%, 6% and 9% so on. Reinforcement particles are the most important parameters influencing the mechanical properties of composites. A limited research work has been reported on Aluminium Metal Matrix Composites reinforced with B4C. Mostly used Reinforcement is SiC, because it is chemically compatible with aluminium and forms an adequate bond with the matrix without developing inter-metallic phase and has other advantages such as excellent thermal conductivity, high machinability, good workability and low cost [1,4-6]. This study investigates the influence of boron carbide on mechanical properties of Aluminium LM13 Matrix B4C Reinforced Composites. 2. Experimental Method and Testing Aluminium Metal Matrix Composite was manufactured by stir casting process with Aluminium-LM13 grade as base metal and boron carbide as reinforcement. LM 13 is an alloy of Al with Si, Cu, Mg etc. and it is suitable for very critical thermal parts. Boron Carbide has grain size of 33μ. It has good wear properties and Cost of this material is very high. It will give good interfacial bonding with the matrix alloy. Boron carbide is good reinforcement material for making composites, especially with aluminium. Particles distribution was found to be better in Al–B4C composites as compared to Al–SiC and Al–Alumina composites. Aluminium alloy LM13 is melted using Open Hearth Furnace. After some time preheated B4C particles are introduced into the furnace mixed up withmatrix and Stir it using iron rod. After mixing of both with matrix and reinforcement molten metal is poured in to sand moulds and allowed to cool and solidify, after some time cast specimens were with drawn from the moulds. Using a K-type thermocouple temperature at the sand mold 1mm away from the mould cavity is measured. Based on the measurement, cooling curves (temperature-time graph) were drawn and cooling rate is analysed with varying weight Percentage of boron carbide from 3% to 9%. Fig. 1 shows experimental setup for measuring temperature.
Fig. 1. Experimental setup for measuring temperature
In order to investigate the influence of boron carbide on mechanical properties of Aluminium Metal Matrix Composites, microstructure evaluation, hardness test and tensile test were conducted. Microstructure analysis is performed using an Inverted metallurgical microscope. Specimen is prepared by etching with diluted hydrofluoric acid after polishing on disc polisher. Microstructure was observed for 200xmagnification. Macro Hardness test was performed using Brinellhardness tester by applying a load of 1000N for 30 seconds .Test were repeated for 5 times in all specimens. Tensile Test is performed on Universal Tensile Testing equipment by setting a load of 10000N. Specimens were prepared to ASTM standard E8M with a gage length of 45mm and gage diameter of 9mm. Fig. 2. Shows specimen prepared for tensile test. Izod and Charpy Impact tests were performed using impact testing model IT13. Fig . 3. Shows specimen prepared for impact test and experiments were repeated five times.
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Fig. 2. Tensile testing specimen
Fig. 3. Impact testing specimen
3. Results and Discussion 3.1. Cooling rate and Microstructure evaluation Fig. 4.shows the changes in temperature with weight Percentage of boron carbide, and it is found that temperature initially increases then decreases after a period of time. Cooling rates are measured from the graph and found 30C/minute, 3.80C/minute and 4.60C/minute for for weight Percentage of boron carbide 3%, 6% and 9% respectively. Hence it can be inferred that increasing the weight Percentage of boron carbide lead to reduction of cooling rate or increase in solidification time.Fig. 5 shows the variation in microstructure (200X Magnification) with variation in reinforcement in Aluminium Metal Matrix Composites .The microstructure indicates the presence of B4C particles in the matrix. Whitish area is entirely representing base material aluminium matrix and remaining dark black particle area represents the reinforcement. Identification of the variation in microstructure, average grain size was measured using Metal Vision Software. Average grain size values were found to be 0.97 microns, 0.85 microns and 0.79 microns for weight Percentage of boron carbide 3%, 6% and 9% respectively. Microstructure is
K.T Akhil/ Materials Today: Proceedings 4 (2017) 7202–7207
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found fine in composite with high weight percentage of boron carbide and microstructure is observed coarse in composite with low weight percentage of boron carbide. Grain size is measured using metal vision software and found much higher in composite with low weight percentage of boron carbide compared to composite with high weight percentage of boron carbide. Mechanical properties were improved with reducing grain size [6-7].
Fig. 4. Cooling Curves of cast components with varying weight Percentage of boron carbide
(a)
(b)
(c)
Fig. 5. Variation in microstructure with varying weight Percentage of boron carbide (a) 3% (b) 6% (c) 9%
3.2. Hardness Test Evaluation Fig. 6 shows the hardness variation with variation in reinforcement in Aluminium Metal Matrix Composites. Hardness values were measured to be 84.4 BHV, 89.8 BHV, and 94.2 BHV for weight Percentage of boron carbide 3%, 6% and 9% respectively. Hardness was found increasing with increase with reinforcement boron carbide in Aluminium Metal Matrix Composites. This is due to increasing in particles in the matrix case an additional trigger to nucleation rate and causesa decrease in grain size which lead to increase in hardness [6-7].
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K.T Akhil/ Materials Today: Proceedings 4 (2017) 7202–7207
Fig. 6. Changes in hardness with weight Percentage of boron carbide
3.3. Tensile Test Evaluation Fig.7 shows the Ultimate tensile strength variation with variation in reinforcement in Aluminium Metal Matrix Composites. Ultimate Tensile stress values were measured to be 125.2 MPa, 135.6 MPa and 145.8 MPa for weight Percentage of boron carbide 3%, 6% and 9% respectively. Ultimate tensile strength were found increasing with increase with reinforcement boron carbide in Aluminium Metal Matrix Composites. This is due to grain refinement of composite with high reinforcement boron carbide.
Fig. 7. Changes in tensile strength with weight Percentage of boron carbide
3.4. Impact Test Evaluation Fig. 8 shows variation in impact strength with variation in weight Percentage of boron carbide for Charpy and Izod tests. Impact strength values for Charpy test was measured to be 54 kJ/m2, 58 kJ/m2 and 69 kJ/m2 for weight Percentage of boron carbide 3%, 6% and 9% respectively. For Izod test, values of 58 kJ/m2, 61 kJ/m2, and 72 kJ/m2 were measured above mentioned weight Percentage of boron carbide. Impact strength was found increases with increase with reinforcement boron carbide in Aluminium Metal Matrix Composites. This is due to grain refinement of composite with high reinforcement boron carbide.
K.T Akhil/ Materials Today: Proceedings 4 (2017) 7202–7207
7207
Fig. 8. Changes in impact strength with weight Percentage of boron carbide
4. Conclusion Cooling rate and Mechanical properties such as Hardness and Tensile strength of Aluminium Metal Matrix Composites were improved with Percentage of boron carbide. Hardness from 84.4 BHV to 94.2 BHV and Ultimate tensile strength from 125.2 MPa to 145.8 MPa and Impact strength from 70 kJ/m2 to 64 kJ/m2 were increased with increase in Percentage of boron carbide from 3% to 9% in LM13 matrix. This is due to fast nucleation rate cause grain refinement in composite with high reinforcement boron carbide. References [1]. GopalaKrishna. “Effect Of Boron Carbide Reinforcement On Aluminium Matrix Composites”, International Journal Of Metallurgical & Materials Science And Engineering(Ijmmse)”,3, 41-48. [2]. Toptan. “ Processing And Microstructure Characterization Of Aluminium alloy 1070 And Aluminium alloy 6063 Matrix B 4c P Reinforced Composites ”, Journal Of MaterialsAnd Design, 31, 513-519. [3]. Neelima Devi “Micro Structural Aspects of Aluminium Silicon Carbide Metal Matrix Composite”, Int. Journal of Applied Sciences and Engineering Research, 2, 48-54. [4]. Shorowordi “Microstructure And Interface Characteristics Of B4c, Sic And Al2O3 Reinforced Al Matrix Composites: A Comparative Study”, Journal Of MaterialsProcessing Technology, 142, 738-743. [5]. Cun-Zhu Nie “Production of Boron Carbide Reinforced 2024 Aluminium Matrix Composites by Mechanical Alloying “, Materials Transactions, 48, No. 5, 2007. 990 - 995. [6]. K.T. Akhil, Sanjivi Arul, R.Sellamuthu,”The effect of section size on cooling rate, microstructureand mechanical properties of A356 aluminium alloy in casting”, Procedia material science 5, 2014, 362-368. [7]. K.T. Akhil, Sanjivi Arul, R.Sellamuthu,”The Effect of Heat Treatment and Aging Process on Microstructure and Mechanical Properties of A356 Aluminium Alloy Sections in Casting”, Procedia engineering 97, 2014, 1676 – 1682.