Hot deformation behavior and microstructure evolution of annealed Al-7.9Zn-2.7Mg-2.0Cu (wt%) alloy

Abstract

Hot compression test of annealed Al-7.9Zn-2.7Mg-2.0Cu alloy was carried out on a thermo-mechanical simulator (Thermacmaster-Z). The hot deformation behavior of the alloy was studied, and the processing map at the strain of 0.7 was established. The processing map exhibited three stable domains with high efficiency (> 30%), which suggested that good hot workability was obtained for the studied alloy. The continuous dynamic recrystallization (CDRX) and discontinuous DRX (DDRX) by PSN were considered the recrystallization mechanisms at low deformation temperature. The particles promoted the recrystallization by stimulating nucleation at the low deformation temperature. The necklace grains were developed along the original grain boundaries through progressive rotation of subgrains in the studied alloy. The effect of PSN was weaker with increasing the deformation temperature, and CDRX was the dominant recrystallization mechanism at high deformation temperature. (C) 2018 Elsevier B.V. All rights reserved.