Superplasticities of Rolled AZ91 Magnesium Alloys
Wei Yinhong, Wang Qudong, Zhou Haitao Zhu Yanping, Ding Wenjiang, Y. Chino , M. Mabuchi (The National Engineering Research Center of Light Metal Net Forming, College of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200030) ( Institute for Structural and Engineering Materials, Nagoya 462～8510, Japan)
The high strain rate superplastic deformation properties and characters of rolled AZ91 magnesium alloys at temperatures ranging from 623K to 698K (0.67T m～0.76T m) and at high strain rates ranging from 10 -3 s -1 to 1s -1 were investigated in this study. Rolled AZ91 magnesium alloys obtained excellent superplasticity with the maximum elongation to failure of 455.05% at 623K and strain rate of 10 -3 s -1 , and its strain rate sensitivity is high up to 0.64. The dominant deformation mechanism in high strain rate superplasticity is still grain boundary sliding (GBS). The main accommodation mechanism was microcavities coalescences, which was observed obviously in this study.