2011 Volume 52 Issue 8 Pages 1581-1584
A study of the effect of chemical composition on microstructure and hardness of the as-cast and homogenized Zn-Al-Cu alloys was carried out. Five different composition alloys were prepared and they were homogenized at 623 K for 648 ks in order to eliminate the dendritic structure. Rockwell “B” hardness was determined in the as-cast and homogenized alloys. XRD diffraction analysis of the as-cast and homogenized alloys indicated the presence of the α, η, ε, θ, τ′ and β phases and α, η, ε, θ, and τ′ phases, respectively. The hardness of both the as-cast and homogenized alloys increased with the increase in volume fraction of the Cu-containing ε, θ, and τ′ phases. A multiple-linear regression analysis permitted to obtain the two equations, HRBAs-cast=97.5+6.8ln(at%Cu)-4.7ln(at%Zn) and HRBHomogenized=52.1+3.6ln(at%Cu)-27.5ln(at%Zn), to assess the hardness in the as-cast and homogenized Zn-Al-Cu alloys.