A Tension Observation and Fracture Mechanics of TRIP Steel

摘要

Stress-induced transformation of retained austenite to martensite has been investigated using in-situ tensile test. Moreover,EBSD technique has been used to analyze distribution and stability of retained austenite in this paper. Fine retained austenite was detected and matrix in the ferrite was more stable. Coupled with transformation,fracture was postponed and stress relaxation was found. In the deformation process,slip band has been found in inner ferrite and it had a direction of 45° to the tensile stress. Crack origin firstly appeared in the Vgap and inclusions,then expanded and connected. The trend of crack often generates break,namely the crack passivated by the transformation of retained austenite to martensite.