Anisotropy investigation of an ECAP-processed Mg-Al-Ca-Mn alloy with synergistically enhanced mechanical properties and corrosion resistance

Anisotropy of a 32-pass equal channel angular pressing (ECAP) processed Mg-3.7Al-1.8Ca-0.4Mn (wt%) alloy with synergistically enhanced mechanical properties and corrosion resistance was investigated. Compared with coarse alpha-Mg grains and discontinuous network Al2Ca phase in as-cast alloy, the ECAP alloy exhibits homogeneous fine alpha-Mg grains (~2.6 mu m), but refined Al2Ca particles show different distribution in three planes, which is network in the extrusion plane (EP), uniform in normal plane (NP) and bandlike in transverse plane (TP). Refinement of microstructure after ECAP resulted in the synergistically enhanced mechanical and corrosion performances in three planes (directions). Moreover, due to grain refinement, the protective film was easily produced on the ECAP alloy, resulting in different corrosion mechanisms developed between ECAP and as-cast alloys. The main factors effecting anisotropic properties of ECAP alloy are Al2Ca distribution and texture of alpha-Mg. Based on the anisotropy investigations, grain size in several microns and high (0001) basal texture density are necessary to realize RE-free Mg-Al-Ca-Mn alloys with synergetic high strength and good corrosion performance. (C) 2022 Elsevier B.V. All rights reserved.