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

The γ-α′ 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-ɛ MT. The orientation dependence of slip deformation prior to the γ-ɛ MT results in the development of γ-α′ MT in [ 1 ¯   1   1 ] -, [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 ] -, [0 1 2]-crystals the γ-α′ MT might occur at T = 300 K but after pre-deformation at T = 77 K.