High Temperature Compression Deformation Characteristics and Hot Processing Map of Austenite-based Low-density Steel

The high temperature compression deformation characteristics of Fe-30.79Mn-8.51Al-1.01Si-0.86C-0.49Mo (mass fraction) at 900-1 050℃ and 0.01-5.00 s^-1 was investigated by thermal simulation compression test, and the hot processing map of the steel was constructed.The results show that the flow stress curves of the steel possesses strain strengthening, strain rate strengthening and dynamic recrystallization softening. The deformation instability caused by the microcracks in the deformation microstructure occurs when the applied deformation strain, temperature and strain rate are all low (20%, 950℃,0.01 s^-1). Under the deformation condition of medium strain high deformation temperature and high strain rate (40%, 1 050℃, 5.00 s^-1), deformation instability due to inhomogeneous plastic deformation occurs in the deformation microstructure. The hot processing map constructed based on the dynamic material model theory and Prasad instability criterion can be used to predict the deformation instability region of the steel.