Hot deformation behavior of spray-deposited Al-Zn-Mg-Cu alloy

摘要

The flow behavior of spray-deposited Al-10.21Zn-2.76Mg-l.45Cu-0.16Zr (wt.%) alloy has been systematically investigated by thermal compression tests with temperature and strain rate ranging from 613 K to 733 K and 0.001-1 s~(-1) respectively. Microstructural observations revealed that the average grain size of spray-deposited alloy was below 25 μm due to the high cooling rate. Both relatively high temperature and low strain rate could promote the formation of dynamic recrystallization (DRX). The stress level of the alloy decreased with increasing deformation temperature and decreasing strain rate, which could be characterized by a Zener-Hollomon parameter in the hyperbolic-sine equation. Furthermore, the strain-dependent constitutive equation could lead to a good agreement between the calculated and measured flow stresses in the elevated temperature range for spray-deposited alloy. The deformation activation energy for spray-deposited alloy was relatively lower than that of the as-cast alloy owing to ultrafine grains and high supersaturated solid solubility.