Flow stress behavior of 7150 aluminum alloy during hot compression deformation at elevated temperature

The flow stress behavior of 7150 aluminum alloy during hot compression deformation was studied by thermal simulation test at the deformation temperature of 300-450 ℃ and the strain rate of 0.01-10 s-1 on the Gleeble-1500 thermal-mechanical simulator.The results show that the flow stress increases with increasing strain and tends to be constant after a peak value.The peak stress increases with increasing strain rate,and decreases with increasing deformation temperature,which can be represented by a Zener-Hollomon parameter in the hyperbolic sine equation with the hot deformation activation energy of 226.6988 kJ/mol.With increasing temperature and decreasing strain rate,the elongated grains in the deformed samples are coarsened and the size of subgrain increases;the number of fine grain in grain boundary also increases,indicating that the main softening mechanism of the alloy during hot compression deformation transforms from dynamic recovery to dynamic recrystallization.