The Effect of Variant Selection on Texture of TWIP/ TRIP Steels During Uniaxial Tensile Loading

The aim of the present manuscript is to reveal the role of variant selection associated with the γ→ε and γ→ε→α’ transformations in the resulting texture of γ, ε and α’ phases of FeMnCr steels during uniaxial loading. Tensile tests were carried out at temperatures well above and close to the martensite start temperature of the ε phase (Msε). Pole figures were obtained from the cross section of the fractured specimens by X-ray diffraction (XRD). The γ texture developed regardless of test temperature. It was found that the ratio of diffracted intensity in the 0° and ~70° directions with respect to tensile axis notably changed with test temperature. The difference was caused by variant selection accompanying the γ→α’ transformation. At high temperatures, α’ martensite formed only in the ~70° directions, where the mechanical driving force is large. At lower temperatures, however, α’ martensite formed in the ~70° and 0° directions as well. It is also shown that stress/strain induced ε martensite can only form in the ~70° directions. The results apply for all three examined steels