Effect of Isothermal Treatment on Mechanical and Tribological Properties of Alloy Zn – 40% Al – 2% Cu – 2% Si

The effect of isothermal exposure at temperatures from 100°C to 250°C for 8 hours on the structure, mechanical and tribological properties of the Zn – 40% Al – 2% Cu – 2% Si alloy produced by chill casting is studied. The isothermal treatment eliminates dendritic segregation yielding a coarse-grained polyhedral structure containing an α-solid solution with fine inclusions of silicon and zinc-rich phase. Increase in the temperature of the isothermal exposure leads to decrease in the hardness and strength and increase in the ductility, in the coefficient of friction and in the wear magnitude while reducing the average roughness of the alloy surface.