Study on Hot Workability of Al-5.87Zn-2.07Mg-2.28Cu Alloy Using Processing Map

Hot compression tests of as-homogenized Al-5.87Zn-2.07Mg-2.28Cu alloy were performed at the deformation temperature range of 350-450A degrees C and a strain rate range of 0.001-1 s(-1). Based on the dynamic materials model and Prasad's instability criterion, the processing map at the true strain of 0.69 was established to evaluate the workability of the alloy, and the related microstructures were investigated. The results show that the flow stress declines with increasing temperature and decreasing strain rate. The high-power dissipation efficiency of stable domains can be mainly attributed to the occurrence of dynamic recrystallization. Flow instability is prone to occur under the condition of low temperature and high strain rate due to the initiation and the propagation of micro-cracks. According to the processing map and corresponding microstructure characteristics, the optimum processing parameters are in the temperature range of 390-430A degrees C and the strain rate range of 0.005-0.032 s(-1).