Abstract:Tensile behaviors of an AZ80 alloy were investigated by elongation-to-failure tensile tests at 300, 350, 400 and 450 °C, and strain rates of 10^-2 and 10^-3 s^-1. Strain-rate-change tests from 5×10^-5 s^-1 to 2×10^-2 s^-1 were applied to study deformation mechanisms. The experimental data show that the material exhibits enhanced tensile ductilities of over 100% at 400 and 450 °C with stress exponent of 4.29 and activation energy of 149.60 kJ/mol, and initial fine grains preserve in evenly deformed gauge based on microstructure studies. The enhanced tensile ductilities are rate controlled by a competitive mechanism of grain boundary sliding and dislocation climb creep, based on which a model can successfully simulate the deformation behavior.

Key words: AZ80 magnesium alloy; tensile behavior; superplasticity; creep; stress exponent