Tensile flow and work hardening behaviors of ultrafine-grained Mg-3Al-Zn alloy at elevated temperatures

摘要: Abstract Tensile flow behavior of ultrafine-grained Mg-3Al-Zn alloy processed via mechanical milling, hot-press consolidation followed by extrusion has been determined in the temperature range from 300 K to 523 K and strain rate 10−2 10−4 s−1. The effects on work hardening are successfully analyzed derived Lukac Balik expression. microstructure evolution shows that dislocation density increases 1.59×1016 m−2 3.04×1016 m−2 stage decreases 3.97×1015 m−2 softening stage, which is accordance with apparent activation energy value 66.71 kJ/mol 10−4 s−1 at suggests dominant mechanism GBS accommodated slip controlled grain boundary diffusion, further proved formation cavities filaments during tensile test. analysis indicates multiplication contributes process, while cross climb dislocations as well play a role process.