Microstructural and mechanical properties of AZ31 magnesium alloy with Cr addition and CO 2 incorporation during processing

Abstract

AZ31 Mg-alloy with ∼5 wt.% Cr and incorporated with CO 2 during processing were produced using the disintegrated melt deposition technique. The effect of Cr addition and CO 2 incorporation on the microstructural and mechanical properties was investigated after extrusion. Microstructural investigation revealed that the addition of Cr (AZ31-5Cr) significantly refined the grain size, and the incorporation of CO 2 (AZ31-5Cr-CO 2) resulted in the in situ formation of chromium carbide (Cr 23C 6) phase. The evaluation of mechanical properties indicated that when compared to the AZ31 base alloy, both AZ31-5Cr and AZ31-5Cr-CO 2 showed significant improvement in the strength properties. Based on the structure-mechanical properties correlation, it was identified that in AZ31-5Cr, Cr acted as a metallic reinforcement that improved the hardness, tensile and compressive yield strengths. In AZ31-5Cr-CO 2, the in situ formed Cr 23C 6 phase acted as a strengthening phase and enhanced the mechanical properties, which were significantly higher than those of AZ31 base alloy and AZ31-5Cr. © 2012 Elsevier B.V. All rights reserved.