Microstructural Evolution and Strengthening of AM90 Magnesium Alloy Processed by ECAP

Abstract

Equal-channel angular pressing (ECAP) was applied on AM90 magnesium alloy using processing route B <inf>C</inf> at 275?C up to four passes. Microstructural evolution and the corresponding modification in mechanical properties (strength, elongation and hardness) corresponding to the number of ECAP passes were evaluated using X-ray diffraction (XRD), electron backscatter diffraction, scanning electron microscopy, transmission electron microscopy, tensile test and microhardness test. Shear deformation was found to refine the microstructure by breaking it into smaller grains formed by dislocation reconstruction. Tensile strength and hardness were found to increase by ? 128 and 23%, respectively, for ECAP-processed 2-pass sample in comparison with that of the homogenized condition. After two passes, tensile strength and hardness started decreasing even though the grain size was still decreasing, which was found to be associated with texture modification during ECAP processing as observed by XRD analysis. © 2017, King Fahd University of Petroleum & Minerals.