High temperature tensile behaviors of extruded and rolled AZ31 Mg alloy

摘要

High temperature tensile ductilities and deformation mechanisms of an extruded and rolled AZ31 Mg alloy were investigated.Elongation-to-failure tests were conducted under constant T-head velocity and constant temperatures ranging from 300℃ to 450℃.Strain-rate-change tests were conducted under varying strain rate from 5×10-5s-1to 2×10-2s-1and constant temperature from 300℃ to 450℃.Experimental results show that the maximum elongation of the AZ31 alloy with an average grain size of about 19μm is 117%at strain rate of 10- 3s-1 and temperature of 450℃.Stress exponent and activation energy were characterized to clarify the deformation mechanisms.The enhanced ductility is dominated by solute drag dislocation creep,and the major failure mechanism is cavity growth and interlinkage.