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

Development of lath martensite structure in low carbon high alloy steel was in-situ observed 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, transformation proceeds along the growth direction of martensite block formed initially in the prior austenite grain. Finally, transformation takes place in the neighbors of transformed martensite block.