Flow stress and softening behavior of 7085 aluminum alloy during compression deformation at elevated temperature

The flow stress and softening behavior of furnace-cooled 7085 aluminum alloy were studied by isothermal compression in the condition of 350~450 ℃,strain rate range of 0.001~0.1 s 1and strain range of 0~0.6.The results show that the flow stress increases rapidly at the initial stage of deformation,and gradually softens into steady with increasing strain.The peak flow stress increases with increasing strain rate or decreasing deformation temperature.The flow stress of aluminum alloy 7085 during hot compression deformation can be expressed by hyperbolic sine equation including Arrhenius term.The relationship between strain and constitutive equation of parameters including activation energy,stress index and structure factor have been also analyzed and founded.It is shown that constitutive equation parameters decrease with increasing strain.The differences of flow stress can be explained based on dynamic recovery and dynamic recrystallization as well as second phase particles.