Experimental investigation of hardness and effect of wear on sintered composites containing AA6061 matrix and TiB₂/Al₂O₃reinforcements

Abstract

Materials prepared using powder metallurgy route exhibit dimensional stability which is required to manufacture critical parts such as brake pads, inlet valves and nozzles. In this paper, composite materials consisting of 5 and 10 wt. % of Titanium-diboride reinforcement in AA6061 aluminium alloy was produced by the sintering process via green compaction. 2 wt. % of alumina was added as the secondary reinforcement to produce the hybrid composites. The produced composites and its hybrid were compared with the base material AA6061 to determine the changes in its density, wear and hardness. The green density and sintered density of the composites and its hybrids reduced by as much as 8.47 % compared to the respective theoretical density. Microscopic examinations showed that the addition of alumina with the Titanium-diboride reinforcement increased the wear resistance of the hybrid composites by 1.22 % compared to the base material. The hardness of the sintered composite increased with the addition of the two reinforcement materials. The hardness for the hybrid composite increased by 74.94 % compared to the base material. After wear test, the hardness of the base material reduced by 6.83 % but the hardness of hybrid composite having the highest composition of both reinforcement particles increased by 6.36 %. The study revealed that the sintering process and subsequent hardening of the composites and its hybrid enhance its hardness property compared to the base material. Interestingly, the wear which leads to the changes in its tribological properties increased the hardness property of the composite and its hybrid.

Nanoparticles reinforced joints produced using friction stir welding: a review

“…The spacing between these bands is equal to the distance that the tool covers while moving forward in every single rotation. Researchers reported that such macrostructures were formed due to the variation in grain size, particles and the precipitates distribution, crystallographic textures, dislocation density, and the chemistry due to the inter-mixing of the dissimilar alloys [15,[39][40][41][101][102][103][104][105][106][107][108]. Krishnan [109] during FSW of dissimilar AA6061-AA7075 alloys at different welding parameters reported that these variations were caused due to the frictional heat imparted to the material to heat and the forward movement of the rotating tool that extrudes the material about the RS that leads to the formation of the banded structure during the rotational motion of the FSW tool.…”

Mechanical and wear characteristics of (Al7075/SiC/Gr/Zr) hybrid metal matrix composites using ultrasonic assisted stir casting process

“…Examined the results indicating 15% B 4 C is best for machinability and surface characteristics. Raja and Prakash[22] created AA6061/TiB 2 /Al 2 O 3 hybrid metal matrix composite using powder metallurgy.…”