Processing and characterization of the microstructure and mechanical properties of Al6061-TiB₂ composite

Abstract

In the present research, aluminum metal matrix composites were processed by the stir casting technique. The effects of TiB₂ reinforcement particles, severe plastic deformation through accumulative roll bonding (ARB), and aging treatment on the microstructural characteristics and mechanical properties were also evaluated. Uniaxial tensile tests and microhardness measurements were conducted, and the microstructural characteristics were investigated. Notably, the important problems associated with cast samples, including nonuniformity of the reinforcement particles and high porosity content, were solved through the ARB process. At the initial stage, particle-free zones, as well as particle clusters, were observed on the microstructure of the composite. However, after the ARB process, fracturing phenomena occurred in brittle ceramic particles, followed by breaking down of the fragments into fine particles as the number of rolling cycles increased. Subsequently, composites with a uniform distribution of particles were produced. Moreover, the tensile strength and microhardness of the ARB-processed composites increased with the increase in the reinforcement mass fraction. However, their ductility exhibited a different trend. With post-deformation aging treatment (T6), the mechanical properties of composites were improved because of the formation of fine Mg₂Si precipitates.

Keywords

stir casting / accumulative roll bonding / aging treatment / mechanical properties / microstructural characteristics / TiB₂ ceramic particle

References

[1] Tjong SC. Novel nanoparticle-reinforced metal matrix composites with enhanced mechanical properties. Adv. Eng. Mater., 2007, 9(8): 639.

[2] Kok M. Production and mechanical properties of Al₂O₃ particle-reinforced 2024 aluminum alloy composites. J. Mater. Process. Technol., 2005, 161(3): 381.

[3] Chen R, Iwabuchi A, Shimizu T. The effect of a T6 heat treatment on the fretting wear of a SiC particle-reinforced A356 aluminum alloy matrix composite. Wear, 2000, 238(2): 110.

[4] Cöcen Ü, Önel K. Ductility and strength of extruded SiC_p/aluminium-alloy composites. Compos. Sci. Technol., 2002, 62(2): 275.

[5] Sharifi EM, Karimzadeh F, Enayati MH. Fabrication and evaluation of mechanical and tribological properties of boron carbide reinforced aluminum matrix nanocomposites. Mater. Des., 2011, 32(6): 3263.

[6] Mazahery A, Ostadshabani M. Investigation on mechanical properties of nano-Al₂O₃-reinforced aluminum matrix composites. J. Compos. Mater., 2011, 45(24): 2579.

[7] Dey D, Bhowmik A, Biswas A. Wear behavior of stir casted aluminum-titanium diboride (Al2024-TiB₂) composite. Mater. Today: Proc., 2020, 26, 1203

[8] Alizadeh M, Paydar MH. Fabrication of nanostructure Al/SiC_P composite by accumulative roll-bonding (ARB) process. J. Alloys Compd., 2010, 492(1–2): 231.

[9] Rajeshkumar G, Harikrishna A M, Ajithkumar S. A Comprehensive review on manufacturing methods and characterization of Al6061 composites. Mater. Today: Proc., 2020, 22, 2597

[10] Ravindran S, Mani N, Balaji S, Abhijith M, Surendaran K. Mechanical behaviour of aluminium hybrid metal matrix composites—A Review. Mater. Today: Proc., 2019, 16, 1020

[11] David Raja Selvam J, Dinaharan I, Vibin Philip S, Mashinini P M. Microstructure and mechanical characterization of in situ synthesized AA6061/(TiB₂+Al₂O₃) hybrid aluminum matrix composites. J. Alloys Compd., 2018, 740, 529.

[12] Gajakosh A K, Keshavamurthy R, Ugrasen G, Adarsh H. Investigation on mechanical behavior of hot rolled Al7075-TiB₂ in-situ metal matrix composite. Mater. Today: Proc., 2018, 5(11): 25605

[13] Subramanya R P, Shettigar A K, Mervin A H, Shrikantha S R. Microstructure and mechanical properties of rutilereinforced AA6061 matrix composites produced via stir casting process. Trans. Nonferrous Met. Soc. China, 2019, 29(11): 2229.

[14] Ravikumar M, Reddappa H N, Suresh R. Aluminium composites fabrication technique and effect of improvement in their mechanical properties—A Review. Mater. Today: Proc., 2018, 5(11): 23796

[15] Prabua SB, Karunamoorthy L, Kathiresan S, Mohan B. Influence of stirring speed and stirring time on distribution of particles in cast metal matrix composite. J. Mater. Process. Technol., 2006, 171(2): 268.

[16] Hashim J, Looney L, Hashmi MSJ. The enhancement of wettability of SiC particles in cast aluminum matrix composites. J. Mater. Process. Technol., 2001, 119(1–3): 329.

[17] Srivyas P D, Charoo M S. Application of hybrid aluminum matrix composite in automotive industry. Mater. Today: Proc., 2019, 18, 3189

[18] Amirkhanlou S, Rezaei MR, Niroumand B, Toroghinejad MR. Refinement of microstructure and improvement of mechanical properties of Al/Al₂O₃ cast composite by accumulative roll bonding process. Mater. Sci. Eng. A, 2011, 528(6): 2548.

[19] Moses J J, Dinaharan I, Sekhar S J. Prediction of influence of process parameters on tensile strength of AA6061/TiC aluminum matrix composites produced using stir casting. Trans. Nonferrous Met. Soc. China, 2016, 26(6): 1498.

[20] Ezatpour HR, Torabi-Parizi M, Sajjadi SA. Microstructure and mechanical properties of extruded Al/Al₂O₃ composites fabricated by stir-casting process. Trans. Nonferrous Met. Soc. China, 2013, 23(5): 1262.

[21] El-Sabbagh A, Soliman M, Taha M, Palkowski H. Hot rolling behaviour of stir-cast Al 6061 and Al 6082 alloys-SiC fine particulates reinforced composites. J. Mater. Process. Technol, 2012, 212(2): 497.

[22] Dehkordi HF, Toroghinejad MR, Raeissi K. Fabrication of Al/Al₂O₃/TiC hybrid composite by anodizing and accumulative roll bonding processes and investigation of its microstructure and mechanical properties. Mater. Sci. Eng. A, 2013, 585, 460.

[23] Ardakani MRK, Amirkhanlou S, Khorsand S. Cross accumulative roll bonding—A novel mechanical technique for significant improvement of stir-cast Al/Al₂O₃ nanocomposite properties. Mater. Sci. Eng. A, 2014, 591, 144.

[24] Nageswara rao P, Jayaganthan R. Effects of warm rolling and ageing after cryogenic rolling on mechanical properties and microstructure of Al 6061 alloy. Mater. Des., 2012, 39, 226.

[25] Podymova NB, Karabutov AA. Combined effects of reinforcement fraction and porosity on ultrasonic velocity in SiC particulate aluminum alloy matrix composites. Composites Part B: Eng., 2017, 113, 138.

[26] Hansen N. Hall-Petch relation and boundary strengthening. Scripta Mater., 2004, 51(8): 801.