中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 25 No. 6 June 2015 |
（1. National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University,
Shanghai 200240, China;
2. General Motors China Science Lab, Shanghai 201206, China;
3. College of Engineering, the Ohio State University, Columbus, OH 43210, USA）
Abstract:The hot deformation behavior and workability of pre-extruded ZK60A magnesium alloy were investigated by compression tests in the temperature range of 250-450 °C and the strain rate range of 0.001-10 s-1. The constitutive equation for the pre-extruded ZK60A alloy can be described by hyperbolic sine function. Processing maps were constructed from true strains of -0.2 to -0.8. The alloy experienced complete dynamic recrystallization (DRX) and showed good workability in the temperature range of 300-400 °C and the strain rate range of 0.01-0.001 s-1, where hot working in pre-extruded ZK60A, such as forging, can be carried out. For large deformation to true strain of over -0.5, strain rates above 0.1 s-1 are not recommended at all temperatures, where flow instability such as local strain concentration, twinning deformation, abnormal grain growth, micro-cracks, and shear fracture were observed. Climb-controlled dislocation creep dominates both the plastic deformation and nucleation of DRX of the pre-extruded ZK60A magnesium alloy.
Key words: pre-extruded ZK60A magnesium alloy; hot deformation; processing map; constitutive equation; workability
