Change-channel angular extrusion of magnesium alloy AZ31

Abstract

We report microstructure evolution and mechanical properties of Mg alloy AZ31 processed by a new severe plastic deformation technique, the change-channel angular extrusion (CCAE). Under all of the processing temperatures ranging from 523 to 723 K, grains of the extruded Mg alloys are found to be refined significantly, which is attributed to the grain subdivision and dynamic recrystallization induced by the drastic deformation. We have also found that lowering processing temperature is a relevant factor in yielding finer grain, which as a consequence, gives rise to higher micro-hardness, larger yield and ultimate compressive strength, and more enhanced compressive ratio. The improved mechanical properties of the AZ31 alloys deformed by the CCAE are comparable or even superior to those of the alloys subjected to the equal-channel angular extrusion with several passes, rendering the CCAE an effective and promising approach to impose drastic plastic deformation for further enhancing workability ot Mg alloys. ©2009 The Japan Institute of Metals.