Dendritic solidification microstructure affecting mechanical and corrosion properties of a Zn4Al alloy

In the present article some important trends have been shown regarding the relationship between solidification variables, microstructure, mechanical and corrosion properties of Zn-4 wt%Al alloy castings. The aim of the present work is to investigate the influence of heat transfer solidification variables on the microstructure of Zn-4 wt%Al castings and to develop correlations with mechanical and corrosion properties. Experimental results include transient metal/mould heat transfer coefficient (h_i), secondary dendrite arm spacings (λ₂), corrosion potential (E_Corr), corrosion rate (i_Corr), ultimate tensile strength (σ_u) and yield strength (σ_y) as a function of solidification conditions imposed by the metal/mould system. It was found that a structural dendritic refinement provides both higher corrosion resistance and better mechanical properties for a hypoeutectic Zn4Al alloy.