Microstructure Evolution and Mechanical Properties of an AZ61 Mg Alloy Through Cyclic Extrusion Compression

摘要

Microstructure evolution and mechanical properties of an AZ61 Mg alloy processed by cyclic extrusion compression were investigated. It is shown that CEC process may be applied successfully to AZ61 Mg alloys, and this leads to excellent grain refinement with grain size of ～0.8μm after 15 passes at 573K and to significant improvements in yield strength, ductility and hardness of AZ61 materials with slight compressive strength decreases. Dislocations were induced at initial stage of CEC process, and with increased deformation, tangled dislocations developed to form dislocation boundaries and subgrain boundaries, and then evolved into low angle grain boundaries (LAGBs) and high angle grain boundaries (HAGBs) which was regarded as continuous dynamic recovery and recrystallization (CDRR).