High temperature tensile deformation behavior of AZ80 magnesium alloy
(School of Materials Science and Metallurgy, University of Science and Technology Liaoning, Anshan 114051, China)
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