Fatigue-Property Enhancements of Magnesium Alloy, AZ31B, through Equal-Channel-Angular Pressing (ECAP)

Abstract

The fatigue behavior of magnesium-alloy, AZ31B, pre-strained by Equal-Channel-Angular Pressing (ECAP) was studied as a function of the accumulated plastic-strain level and the orientation of the samples (along and parallel to the ECAP pressing direction). The material was processed via route BC, at 200 oC, for 1, 2, and 8 passes, with and without a back-pressure applied on the billet during ECAP. The low-cycle fatigue behavior of the AZ31B alloy is shown to be anisotropic and texture-dependent. Due to the initial texture orientation, the specimens loaded parallel to the ECAP pressing direction have a longer fatigue life than the samples loaded perpendicular to it. The low-cycle fatigue life of the AZ31B alloy is enhanced by ECAP. The fatigue-property improvement is discussed in the light of the grain-size refinement, enhanced ductility, and texture evolution.