Hot deformation behavior and dynamic recrystallization mechanism of 7050 aluminum alloy with a focus on reduction amount
摘要
This study investigates the hot deformation behavior and dynamic recrystallization (DRX) mechanisms of the 7050 aluminum alloy. Isothermal compression tests were conducted on a Gleeble-3800 thermal simulator at temperatures of 623–743 K, strain rates of 0.005–0.5 s−1, and reductions of 20–60%. Firstly, the flow stress increased with decreasing deformation temperature and increasing strain rate. Secondly, the activation energy for hot deformation was determined to be 193,904.52 J·mol−1, and two constitutive models were developed: one based on peak stress and one incorporating strain compensation. The strain-compensated model exhibited superior predictive accuracy and showed excellent agreement with the experimental results. Additionally, the DRX kinetic equation during hot deformation of 7050 aluminum alloy was calculated. Finally, the DRX mechanisms of the material under different reduction amounts were thoroughly examined using characterization techniques such as optical microscopy (OM) and electron backscatter diffraction (EBSD). Experimental results indicate that for 7050 aluminum alloy deformed at 703 K and a strain rate of 0.05 s⁻1, discontinuous dynamic recrystallization (DDRX) features are observed at 20% reduction. At 40% reduction, continuous dynamic recrystallization (CDRX) begins to develop, and CDRX features become increasingly evident at 60% reduction.