Martensite phase stress and the strengthening mechanism in TRIP steel by neutron diffraction

中性子回折によるマルテンサイト相応力とTRIP鋼の強化機構

Harjo, S.   ; 土田 紀之*; 阿部 淳*; Gong, W.*

Harjo, S.; Tsuchida, Noriyuki*; Abe, Jun*; Gong, W.*

Two TRIP-aided multiphase steels with different carbon contents were analyzed in situ during tensile deformation by time-of-flight neutron diffraction to clarify the deformation induced martensitic transformation behavior and its role on the strengthening mechanism. The difference in the carbon content affected mainly the difference in the phase fractions before deformation, where the higher carbon content increased the phase fraction of retained austenite (). However, the changes in the relative fraction of martensitic transformation with respect to the applied strain were found to be similar in both steels since the carbon concentrations in were similar. The stress contribution from martensite was observed increasing during plastic deformation while that from bainitic ferrite hardly changing and that from decreasing.