Transformation strain and texture evolution during diffusional phase transformation of low alloy steels studied by neutron diffraction

Xu, P. G.   ; Tomota, Yo*; Vogel, S. C.*; Suzuki, Tetsuya*; Yonemura, Masao*; Kamiyama, Takashi*

The ferrite-to-austenite transformation during heating and the austenite-to-ferrite transformation during cooling were investigated by KEK/SIRIUS and LANSCE/HIPPO neutron diffractometers under the stress-free condition. The deviation of ferrite lattice parameter from the linear thermal expansion and contraction during heating and cooling suggested the compressive strain occurred in ferrite phase. The texture memory effect between the cold compression texture of initial martensite and the final texture of ferrite after -- phase transformation was interrupted by the static recrystallization of martensite during step-by-step heating, revealing that the occurrence of texture memory effect was not directly related to the deformation stored energy but related to the transformation strain and the strong variant selection for nucleation.