Multiscale in-situ studies of strain-induced martensite formation in inter-critically annealed extra-low-carbon martensitic stainless steel

An extra low carbon martensitic stainless steel with 16% ultrafine grained metastable reverted austenite was subjected to uniaxial tensile testing and investigated in-situ energy-dispersive synchrotron X-ray diffraction (XRD) electron backscatter (EBSD) reveal the complex interplay between stress, strain transformation. In-situ XRD demonstrated that, upon surpassing yield strength, fraction of declined linearly increasing true which associated transformation-induced plasticity (TRIP). EBSD consistently showed that texture martensite evolved from an initially weak towards a strong 110α′ fiber parallel axis. For first time, stress partitioning (remaining) matrix determined quantitatively during by averaging over values obtained lattice strains for multiple reflections. Martensite accommodates majority applied load while is severely plastically deformed. shows plastic anisotropy in austenite. forward-scatter imaging advanced variant analysis data indicate deformation strain-induced austenite-to-martensite transformation concentrated along boundaries blocks packets are inclined up ∼55° respect direction. These regions were preferred sites formation.