Superplastic Behavior of Friction Stir Processed ZK60 Magnesium Alloy

Abstract

Six millimeter thick extruded ZK60 magnesium alloy plate was subjected to friction stir processing (FSP) at 400 rpm and 100 mm/min, producing fine and uniform recrystallized grains with predominant high-angle grain boundaries of 73%. Maximum elongation of 1800% was achieved at a relatively high temperature of 325°C and strain rate of 1×10−3 s−1. Grain boundary sliding was identified to be the primary deformation mechanism in the FSP ZK60 alloy by superplastic data analyses and surface morphology observation. The superplastic deformation kinetics of the FSP ZK60 alloy was faster than that of the high-ratio differential speed rolled ZK60 alloy.