Grain refinement of AM60/Al2O3p magnesium metal-matrix composites processed by ECAE

Abstract

This paper studies the mechanical properties enhancement of AM60/Al2O3p magnesium metal-matrix nanocomposites by equal channel angular extrusion (ECAE) that is a useful technique to produce bulk nano-structured materials by severe plastic deformation. The present magnesium metal matrix composites (Mg MMCs) with 1, 2 and 5 wt.% of nano-sized Al2O3 particulates for ECAE were fabricated using stir-casting method. Observing the microstructures of MMCs, the more uniform microstructure consisting of grains with an average grain size of ∼ 0.8 µm was observed in the AM60/5wt.%Al2O3p MMC after 4 passes. The hardness of MMCs increases evidently with the increase of the weight percentage of Al2O3p additions and ECAE passes. The optimal hardness of AM60/5wt.%Al2O3p MMC after 4 passes increased to 103.7 HV, which is by 87.2 % higher than that of as-cast AM60.