neutron diffraction study on the deformation of a TRIP-assisted multi-phase steel composed of ferrite, austenite and martensite

その場中性子回折によるフェライト、オーステナイトとマルテンサイトを有する複相TRIP鋼の変形挙動の研究

Lavakumar, A.*; Park, M. H.*; Gao, S.*; 柴田 曉伸*; 興津 貴隆*; Gong, W.   ; Harjo, S.   ; 辻 伸泰*

Lavakumar, A.*; Park, M. H.*; Gao, S.*; Shibata, Akinobu*; Okitsu, Yoshitaka*; Gong, W.; Harjo, S.; Tsuji, Nobuhiro*

Multi-phase steels showing transformation induced plasticity (TRIP), can exhibit an excellent combination of high strength and good ductility by the aid of martensitic transformation during deformation. Even though TRIP-assisted multi-phase steels have been widely used in industry, the role of each phase in the enhancement of mechanical properties is still unclear given their complicated microstructures. In order to understand better the nature of the TRIP effect, the mechanical interaction between different phases at the micro-scale should be clarified. In the present study, the mechanical behavior of a transformation induced plasticity (TRIP) assisted multi-phase steel, has been characterized by neutron diffraction during tensile testing. The result of strain partitioning between the different phases obtained from the neutron analysis revealed that the martensite phase took much more elastic strain than the ferrite and retained austenite phases, which suggests that the work hardening behavior in the present steel is affected by the higher load borne by deformation-induced martensite.