Effect of deformation parameters and Al2Cu evolution on dynamic recrystallization of 2219-O Al alloy during hot compression

Abstract

The properties of Al alloy are significantly affected by the evolution of the microstructure during hot deformation. In this study, the 2219-O Al alloy was tested by hot compression at different temperatures, strain rates and compression ratios. Microstructures were analyzed at different parameters based on scanning electron microscopy and electron backscattered diffraction. With the temperature rising above 350 °C, more Al2Cu particles were dissolved. Instead, the increasing strain rate had a slightly positive effect on the precipitation of Al2Cu. The main dynamic recrystallization (DRX) mechanism in the 2219-O Al alloy was continuous dynamic recrystallization (CDRX) facilitated by fine Al2Cu particles. Particle stimulated nucleation (PSN) and discontinuous dynamic recrystallization (DDRX) were also observed. At 250–350 °C, the rising temperature gradually promoted the DRX with the stable content of fine Al2Cu particles. At 350–450 °C, the decrease of Al2Cu particles with rising temperature weakened the DRX. At 490 °C, all fine Al2Cu particles were dissolved, and the extremely high temperature significantly promoted the migration of grain boundaries, strengthening the DRX. The decreasing strain rate and increasing strain facilitated the DRX.