Superior TRIP effect in a duplex stainless steel and its mechanism studied by neutron diffraction experiments

土田 紀之*; 藤田 晃徳*; 平川 直樹*; 濱田 純一*; 石丸 栄一郎*; Gong, W.   ; 川崎 卓郎   ; Harjo, S.   

Tsuchida, Noriyuki*; Fujita, Akinori*; Hirakawa, Naoki*; Hamada, Junichi*; Ishimaru, Eiichiro*; Gong, W.; Kawasaki, Takuro; Harjo, S.

This study investigated the transformation-induced plasticity (TRIP) effect in duplex stainless steel (DSS), focusing on the influence of deformation temperature on the mechanical properties of 24Cr-5Ni-0.18N DSS. The steel showed an excellent balance of tensile strength and uniform elongation below 183 K due to deformation-induced martensitic transformation (DIMT) of the austenite () phase. The superior TRIP effect was attributed not only to DIMT and enhanced stress and work hardening at lower temperatures, but also to changes in phase interactions and texture evolution. DIMT suppressed crystal rotation, altered stress partitioning among constituent phases, and weakened the texture of the and ' phases. In JIS-SUS329J4L, phase stress, work hardening, and KAM values increased with decreasing temperature, while the texture weakened.