电弧增材制造 2219 铝合金热变形组织演变及本构方程

The hot deformation behavior of wire arc additive manufactured (WAAM) 2219 aluminum alloy was studied by hot compression method, and the deformation temperature was 360-510 ℃, the strain rate was 0. 01-10 s^-1. The effects of temperature and strain rate on the flow stress and microstructure were analyzed. The hot deformation constitutive equation of WAAM 2219 aluminum alloy was established with hyperbolic sinusoid function of Zener-Hollomon parameter. The results show that the hot compression peak stress of WAAM 2219 aluminum alloy decreases gradually with the increase of temperature and the decrease of strain rate. For WAAM alloy, only sliding deformation occurs at 420 ℃ and below, and dynamic recrystallization occurs at 450 ℃ and above. 480 ℃ is the best forging temperature and complete dynamic recrystallization occurs, which can effectively refine the additive grains. The constitutive equation is divided into two stages taking the dynamic recrystallization temperature (450 ℃) as the critical point. The deformation activation energy is 212. 53 kJ ·mol^-1 below the dynamic recrystallization temperature and 163. 37 kJ·mol^-1 above the dynamic recrystallization temperature. The eutectic θ phases distributed along the grain boundaries broke and are solid dissolved in the process of hot compression. The higher the deformation temperature is or the small the strain rate is, the higher the solid solution degree is.