Phase Transformations in a Metastable Fe–18Cr–10Ni Alloy during Megaplastic Deformation

The influence of severe plastic (megaplastic) deformation in a Bridgman anvils on the structure, hardness, and spontaneous magnetization of a metastable Fe–18Cr–10Ni alloy in two initial states, namely, austenitic state after hot plastic deformation and martensitic state after subsequent cold plastic deformation, is investigated. High-pressure (quasi-hydrostatic) torsion at a true strain e = 4.7–5.8 is found to form two martensitic phases, namely, the ferromagnetic α phase with a high specific saturation magnetization and the paramagnetic ε phase. Two dispersed phases, which differ significantly in magnetic respect, largely explain the complex nature of changing the saturation magnetization with the strain and the high hardness of the alloy.