Microstructural characterization and wear properties of mechanically alloyed and sintered Al-4wt.% Cu alloy composites reinforced with TiC and ZrC particulates

Particulate reinforced aluminum metal matrix composites are candidate materials for advanced structural applications owing to the attractive balance of specific stiffness, strength and good wear resistance, thermal conductivity, and low thermal expansion, all of which are the properties of them good functional materials as well. Homogeneously distributed reinforcements (mostly carbide particles) in a matrix structure as well as strong interfacial bonding between the carbide particles and matrix are desirable for good wear resistance. For this purpose, Al-4wt.% Cu composites reinforced with TiC and ZrC particles were fabricated by mechanical alloying to obtain a refined microstructure and a homogeneous particle distribution. The effect of mechanical alloying time on morphology, microhardness and microstructure of the final powder was studied in detail. Optimum time for alloying of both unreinforced and reinforced alloy was determined for sintering This chapter focuses on the influence of mean particle size, type, actual volume fraction and the distribution of carbide particles to sliding wear properties of Al-4wt.% Cu metal-matrix composite reinforced with the different initial particle sizes of TiC and ZrC particulates. Physical properties such as density, hardness, and dry sliding wear resistance of the composites were evaluated and their properties were compared with those of the unreinforced matrix alloy. A higher amount of wear loss was observed in the composite containing fine ZrC particles due to clustering which leads to weak interfacial bonding between the matrix and carbide particles. The sliding wear results also led to the conclusion that coarse carbide particles were more effective for the wear resistance than the fine ones against steel counterface.