Superplasticity and superplastic bulging capability of rolled magnesium alloy
YU Yan-dong 1, 2 , ZHANG Kai-feng 1, JIANG Da-ming 1, ZHENG Hai-rong 1, WANG Chang-li 1 (1.School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China; 2.School of Mechanical and Power Engineering, Harbin Science and Technology Univ ersity, Harbin 150008, China)
Superplasticity of a rolled magnesium alloy Mg-Zn-Z r was investigated at 573 K and a strain rate of 5.56×10 -4 s -1 . The m aximum elongation is 309% and the strain rate sensitivity exponent m is 0.34 . The grain size of the rolled magnesium alloy is 5.9 μm. However, the grain s ize of the specimen deformed to a true strain of 0.3 is 4.5 μm. The grain ref inement is attributed to dynamically continuous recrystallization during the ini tial stage of tensile test. SEM observation shows that the typical cavities are obvious in fracture surfaces of tensile samples after superplastic deformation. Finally, the successful superplastic gas pressure bulging forming experiment pro ves the satisfying superplastic forming capability of the alloy.