Investigation of the effects of T5 and T6 heat treatments on the structural, mechanical, and tribological properties of Zn-40Al-2Cu-0.1Sr alloy

Abstract

To assess the effects of T5 and T6 heat treatments on the structural, mechanical, and tribological properties of Zn-40Al-2Cu-0.1Sr alloy several ingots were produced by the permanent mold casting. The structure and properties of the alloy were investigated by appropriate test procedures. It was observed that the as -cast microstructure of the alloy consisted of alpha dendrites, eutectoid transformation product of alpha+eta phase mixture, copper -rich epsilon (CuZn 4 ), and mu(SrZn x ) phase particles. T5 heat treatment had no significant effect on the dendritic microstructure of this alloy but T6 heat treatment removed it completely. It was also observed that T5 heat treatment decreased the hardness and tensile strength but caused a slight increase in the elongation to fracture of the alloy. T6 heat treatment caused an increase in the hardness and tensile strength of the alloy but decreased its elongation to fracture. It was also observed that both heat treatments (T5 and T6) increased the wear resistance of the alloy. The effects of the heat treatments on the mechanical and tribological properties of the alloy were explained in terms of the observed microstructural changes.