The orientation dependence of γ-α' martensitic transformation in austenitic stainless steel single crystals with low stacking fault energy

摘要

The γ-a' martensitic transformation (MT) during tensile deformation in austenitic stainless steel single crystals of Fe-17% Cr-12% Ni-2% Mn-0.75% Si (wt.%) with low stacking fault energy has been investigated in dependence on crystal axis orientation and test temperature T= 77-300 K by means of X-ray diffraction analysis and transmission electron microscopy. In this steel the γ-α' MT is shown to occur during plastic deformation at T≤ 190 K and after the γ-ε MT. The orientation dependence of slip deformation prior to the γ-ε MT results in the development of γ-α' MT in [111]-, [0 1 1], [1 2 3]- [0 1 2]-crystals with a different defect structure. It is shown that in [1 1 1]-, [0 1 1], [1 2 3]-, [01 2]-crystals the γ-α' MT might occur at T= 300 K but after pre-deformation at T= 77K.