Characterization of 1050Al/Al₃Ni/ZrO₂ hybrid surface composites fabricated by friction stir processing

Abstract

Al/Al3Ni and Al/nano‐ZrO2 mono and Al/Al3Ni/ZrO2 hybrid composites were produced by one‐ and four‐pass friction stir processing (FSP). Then, the microstructure, hardness, and wear performance of the surface composites were evaluated. Results showed that the incorporation of Ni particles into the Al surface and their in situ reaction with the substrate resulted in the development of Al3Ni particles in the stir zone. The formation mechanism of these particles was deeply studied from both thermodynamics and kinetics aspects. Similarly, the four‐pass FSP led to the distribution of ZrO2 nanoparticles and the formation of Al/ZrO2 composites. With the addition of both Ni and ZrO2 particles, a hybrid Al/Al3Ni/ZrO2 composite was produced. This caused a 60% improvement in hardness and a 35% improvement in wear resistance of Al substrate. In the case of monolithic composites, both abrasion and adhesion were responsible for the material removal during the wear test, whereas adhesion was specified as the dominant wear mechanism in the hybrid composite.