Effect of Ca addition on the microstructure, mechanical properties and corrosion behavior of AZ61-Nd alloy

Abstract

The effect of Ca elements on the microstructure, mechanical properties and corrosion behavior of extruded AZ61-1Nd-xCa (x=0, 0.5, 1, 2 wt.%) alloys were investigated. The Al-Nd phase and Al2Ca particles are dynamically precipitated in the extruded alloys. The volume fraction of Al2Ca precipitates increases with the increase of Ca content. Moreover, the addition of Ca can refine the grain size. The tensile strength of the studied alloys remains almost constant and their hardness increases with increasing the Ca content. Regretfully, the presence of Al-Nd phase and brittle Al2Ca phase in the Ca-alloyed AZ61-Nd decreases significantly the elongation. The corrosion resistance of AZ61-1Nd alloy is conspicuously improved by the addition of 1 wt.% Ca, which is due to the uniformly and dispersedly distributed Al2Ca phase acting as a physical barrier. In this work, AZ61-1Nd-1Ca alloy with moderate strength and low corrosion rate was obtained, which is considered as a candidate material for application in marine environment.