Microstructure and Mechanical Behaviors of AZ91 Magnesium Alloy with Thermal Rate Treatment Technique

Abstract

Microstructure and mechanical behaviors of AZ91 cast magnesium alloys with melt superheating and thermal rate treatment technique were studied. Alloy grains thicken at 820°C and refine at 870°C when they contains Mn element and the crucible had no coating on the internal surface. Moreover, the strengthening γ phase is more dispersive and uniform at 870°C. Thermal rate treatment significantly improved the microstructure, mechanical behaviors and casting quality of AZ91 alloy as microstructure of AZ91 alloy reserves some characteristics of the high temperature melt.