Effect of large deformation on microstructure of ZK60 alloy
(1.上海市上海交通大学轻合金网成型国家工程研究中心
2.山西省太原市太原理工大学应用科学学院
3.National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University,Shanghai 200030, China
4.National Engineering Research Center for Light Alloy Net Forming, Shanghai Jiao Tong University,Shanghai 200030, China)
2.山西省太原市太原理工大学应用科学学院
3.National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University,Shanghai 200030, China
4.National Engineering Research Center for Light Alloy Net Forming, Shanghai Jiao Tong University,Shanghai 200030, China)
Abstract: Microstructure evolution of ZK60 magnesium alloy deformed at 623 K by cyclic extrusion compression (CEC) large deformation method was investigated. ZK60 alloy was deformed in the range of accumulated true strain of 0.8？17. The microstructure of evolution was investigated by optical microscope (OM) and transmission electron microscopy (TEM). The results show that microstructure is obviously refined, and homogenous equiaxed microstructure is achieved in the entire range of the examined deformations by subjected to CEC deformation. By increasing the accumulated strain to 17, the grain size decreases into sub-micron regime with about several hundred nanometers. The mechanism of grain refinement in ZK60 alloy by CEC can be attributed to continuous dynamic recovery and recrystallization.
Key words: ZK60 magnesium alloy; cyclic extrusion and compression; continuous dynamic recovery and recrystallization; micros- tructure