Hot deformation and dynamic recrystallization of Al-5Mg-0.8Mn alloy

AbstractThe AA 5083 alloy was deformed in torsion in the ranges 300–500°C and 0.1–1 S−1 to a strain of 5. The flow stress as a function of strain rose to a maximum value then gradually decreased towards a steady state and had a dependence on temperature and strain rate of the traditional form with an activation energy higher than that for pure Al. Optical microstructures of specimens quenched after working ranged from elongated grains at 300°C to recrystallized grains at 500°C. Transmission electron microscope subgrain structures from all conditions of working were more recovered at higher temperatures and lower strain rates. The subgrain diameters are smaller than those in commercial Al mainly as a result of the increased density of particles and this is in agreement with observations in extrusions. Since the degree of recovery is not substantially less than in commercial Al, one is led to confirm the theory that the dynamic recrystallization is caused by particles of <0.6 μm.