Hot Deformation Characteristics and Microstructure Evolution of an Al-Zn-Mg-Ni-Fe-Zr Alloy

摘要

In this study, the hot deformation behavior of a Nikalin alloy with composition of Al-6.2Zn-0.70 Mg-1.07Ni-0.75Fe-0.25Zr has been investigated by hot compression test in temperature range from 400 to 475 degrees C and at strain rate range of 0.001-1 s(-1). By studying the processing map obtained at strain of 0.7, it is concluded that there is a region at the temperature of 450-470 degrees C and the strain rate of 0.001-0.003 s(-1) with the highest efficiency of power dissipation. This region can be assumed as the optimum condition for hot working of this material. According to the microstructure observation, the flow instability manifests cracking and kinking at two regions which have been predicted by the continuum instability criterion, while the microstructure characteristic in the safe domains is mainly related to dynamic recovery (DRV) phenomenon.