Effect of T6 Heat Treatment on Mechanical and Tribological Properties of Fabricated AA7075/ZrB2/Fly Ash Hybrid Aluminum Metal Matrix Composite by Ultrasonic-Assisted Stir Casting Enroute

The microstructural, mechanical, and tribological properties of hybrid aluminum metal matrix composite materials are studied and presented in this research work. The hybrid composite is fabricated through ultrasonic-assisted stir casting in which zirconium diboride (ZrB2) particles (1-10 microns) and fly ash (10-50 microns) are mixed as a reinforcement material. The hybrid aluminum metal matrix composite is fabricated in different categories by varying wt% of ZrB2 as 1, 3, and 5% when the weight % of fly ash is kept constant at 2%. Further, the wear properties of fabricated composites are investigated at ambient temperatures to find the effects of sliding wear under lubricants (Servo TC 15W-40) conditions by using a linear reciprocating wear test. The worn surfaces are subjected to field emission scanning electron microscopy to identify the composites' wear behavior. The base alloy and composites' mechanical properties, such as tensile strength and hardness, are studied under cast and T6 heat-treated conditions. The coefficient of friction under lubricant condition for 5 wt% ZrB2-based T6 heat-treated composite is 0.01466 and for T6 heat-treated base alloy is 0.07197. The specific wear rate of the hybrid aluminum metal matrix composite is decreased by 46.94% as compared to base alloy at 40 N load.