Comparison of 304 stainless steel and Ni–30 wt.% Fe as potential model alloys to study the behaviour of austenite during thermomechanical processing

The applicability of a 304SS austenitic stainless steel and a Ni–30 wt.% Fe alloy as model materials to study the behaviour of austenite during the thermomechanical processing of a C–Mn steel has been investigated. The latter alloy has a stacking-fault energy (SFE) closer to that of a C–Mn steel. The crystallographic texture evolution is similar for both materials, being characterized by gradual crystallite rotations towards the stable end orientations typical of fcc metals. The deformation structures observed in both materials are principally similar, with these structures showing the same orientation dependence. However, at the lowest temperature studied the 304SS starts to form stacking faults in the deformation structure. Overall, it has been concluded that at higher temperatures both materials might be appropriate model alloys for the austenite phase in a C–Mn steel. However, at lower temperatures the Ni–30Fe would be the more appropriate alloy because at these temperatures the low SFE energy of 304SS significantly changes the deformation behaviour of the material.