Investigation of the Mechanical Properties and Wear Resistance of Al6061 Composites Fabricated by Stir Casting Method

Aluminium matrix composites (AMCs), which have better tribological and mechanical properties than other conventional alloys, have a lot of potential for important uses in the automotive, defense, aerospace, marine, agricultural, and nuclear engineering industries. In this work, attempts were made to construct AMCs reinforced with various weight percentages of different reinforcement particles, namely boron carbide (B₄C), titanium diboride (TiB₂), and silicon carbide (SiC), in order to improve the tensile behaviour, hardness, and wear resistance. The reinforcement particles with different weight percentages (1, 3, and 5%) were added to Al6061 using the stir casting technique. This work can be divided into two parts: in the first part, the reinforcement particles were added separately (single-reinforcement composite), while in the second part of this work, hybrid composites (hybrid-reinforcement) were fabricated. The tensile strength, hardness, and wear of the AMCs were investigated. Each experiment was repeated three times to ensure repeatability, and an average was taken. In addition, an optical microscope and a scanning electron microscope were used to characterize the AMCs. The SEM examination shows that the reinforcement particles are distributed evenly throughout the Al6061 matrix. The results of the first part of this investigation show that adding different amounts of TiB₂ and B₄C separately, i.e., as single-reinforcement composite, enhanced the ultimate tensile strength, the composites' hardness, and their wear resistance. The most interesting thing to come out of the data is that adding a small amount of TiB₂ particles increases the hardness of the composites much more than previous research has shown. The results also showed that by adding 1 % wt. of B₄C, and 3 wt.% of TiB₂, the composites had a lower wear rate and higher wear resistance compared to the base alloy. The findings also showed that by adding 5% wt. of SiC, the wear resistance and hardness were enhanced compared with the base alloy. However, 1 % wt. of the particles has a higher ultimate tensile strength.

In the second part of this study, an attempt has been made to fabricate hybrid aluminium matrix composites (Al6061/3% B₄C+TiB₂) at various proportions of TiB₂ (1, 3, 5% wt.). The results showed that (Al6061/3%B₄C+5%TiB₂) has a higher hardness and tensile strength. Due to the porosity in the samples, (Al6061/3%B₄C+1%TiB₂) has a lower wear rate and is more resistant to wear. The most obvious finding to emerge from this study is that adding TiB₂ particles reinforced with Al6061 as a matrix has higher results compared to the other particles that are used.