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

The effects of calcium (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 calcium content. Moreover, the addition of calcium can refine the grain size. The tensile strength of the studied alloys remains almost constant and their hardness increases with increasing the calcium 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.% calcium, 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.

Automated summary

The effects of calcium (Ca) on the microstructure, mechanical properties and corrosion behavior of extruded AZ61-1Nd-xCa (x = 0, 0.5, 1, 2 wt.%) alloys were studied. The addition of calcium increased the volume fraction of Al2Ca precipitates and refined the grain size. The alloys showed consistent tensile strength and increased hardness with increasing calcium content. However, the presence of Al-Nd and brittle Al2Ca phases significantly reduced the elongation. The corrosion resistance of AZ61-1Nd alloy was greatly improved with the addition of 1 wt.% calcium due to the uniformly distributed Al2Ca acting as a physical barrier. The obtained AZ61-1Nd-1Ca alloy with moderate strength and low corrosion rate is considered a candidate material for marine applications.