中國(guó)有色金屬學(xué)報(bào)(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 24 No. 1 January 2014 |
（1. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,
Hunan University, Changsha 410082, China;
2. College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China;
3. Geely Automobile Research Institute Co., Ltd., Hangzhou 311228, China）
Abstract:The flow stress behavior and microstructure development of Al-5Zn-2Mg (7005) aluminum alloy were studied by hot compression tests at deformation temperatures between 300-500 °C and strain rates between 0.05-50 s-1. The deformed structures of the samples were observed by optical microscopy (OM), transmission electron microscopy (TEM) and electron backscattering diffraction (EBSD) analysis. The calculated activation energy is 147 kJ/mol, which is very close to the activation energy for lattice self-diffusion in aluminum (142 kJ/mol). Dynamic recovery is the dominant restoration mechanism during the deformation. At high strain rate of 50 s-1, temperature rise due to deformation heating leads to a significant flow softening. Microstructure observations indicated that the remaining softening after deformation heating correction at high strain rate and the softening observed at high temperature are associated with grain coarsening induced by grain boundary migration during dynamic recovery process.
Key words: 7005 aluminum alloy; deformation; dynamic recovery; flow softening; microstructure evolution
