Variant Selection of Low Carbon High Alloy Steel in an Austenite Grain during Martensite Transformation

In this study, the development of a lath martensite structure in low carbon high alloy steel was observed in situ using high-temperature laser scanning confocal microscopy. The crystallography of the martensite structure was analyzed using electron backscatter diffraction patterns. It was observed that martensite transformation starts from the prior austenite grain boundary. Then, the variant (Sigma 1) of another packet belonging to the same bain correspondence was observed in the early stage of martensite transformation. Another block in the same packet was observed in the next stage of martensite transformation. Finally, transformation occurred among the neighbors of the transformed martensite block.