Tensile Deformation Behavior of 1 GPa-Grade TRIP-Aided Multi-microstructure Steels Studied by In Situ Neutron Diffraction

摘要

Tensile deformation behavior and the TRIP effect of 1 GPa-grade TRIP-aided multi-microstructure (TRIP) steels were studied by in situ neutron diffraction experiments during tensile test. The effect of retained austenite (γ_R) shape on TRIP effect in the 1 GPa-grade TRIP steels was focused on. In the static tensile tests, the 1 GPa-grade TRIP steel with the γ_R shape of needle-like showed better uniform elongation, whereas the tensile strength was almost the same as the TRIP steel with the γ_R shape of blocky. The reasons for the better uniform elongation of the needle-like TRIP steel were discussed from the viewpoints of phase strain and deformation-induced martensitic transformation behavior obtained by the neutron diffraction experiments. As a result, the difference of phase strains and the transformation rate are found to play an important role in the better uniform elongation.