Tribological potential of particulate composites with ZA-27 alloy matrix

Abstract

The tribological effects of particle reinforcement on the wear behavior of ZA-27 alloy composites were investigated. The ZA-27/Al2O3, ZA-27/SiC, ZA-27/Gr, ZA-27/SiC/Gr composites with different particle content were produced by the compocasting procedure. Tribological properties of unreinforced alloy and composites were studied, using block-ondisk tribometer under dry friction conditions at different specific loads and sliding speeds. The worn surfaces of samples were examined by the scanning electron microscopy (SEM). The obtained results clearly indicate that reinforcement with Al2O3, SiC or/and graphite particles could significantly improve tribological properties of ZA-27 alloy. The effects of reinforcement on wear behavior depend on type of particles, their content and combination (hybrid composites), as well as sliding speed and applied load. The wear mechanisms of composites in tested conditions are explained by micro cracking tendency and the formation and destruction of mechanical mixed layers (MMLs).