Hot deformation behavior and processing map of squeeze cast ZK60 magnesium alloy
(1.黑龙江省哈尔滨市哈尔滨工业大学材料科学与工程学院
2.黑龙江省哈尔滨市黑龙江工程学院材料与化学工程系
3.School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China)
2.黑龙江省哈尔滨市黑龙江工程学院材料与化学工程系
3.School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China)
Abstract: The deformation behavior of squeeze cast ZK60 magnesium alloy was investigated by compressive tests conducted at temperatures of 250？450 ℃ and strain rates of 0.001？10 s？1 with Gleeble—1500D thermal simulator system. The hot deformation behavior of squeeze cast ZK60 magnesium alloy was characterized using processing map developed on the basis of the dynamic materials model. The processing map gives safe “processing windows” in which the processes of dynamic recovery and dynamic recrystallization occur. It reveals that the dynamic recrystallization domain occurs at 375 ℃ and strain rate of 0.001 s？1, and its power dissipation efficiency approximately corresponds to 36%, which should be considered the optimum parameters for hot working of squeeze cast ZK60 magnesium alloy. The variation of the instability parameter ξ(ε) with temperature and strain rate constitutes an instability map, which is used for delineating the region of flow instability. The material exhibits flow instability which should be avoided in mechanical processing.
Key words: hot deformation; processing map; ZK60 magnesium alloy; dynamic recrystallization; flow instability