Influence of High-pressure Quenching on the Microstructure, Martensite Transformation, and Mechanical Properties of 0.2 Mass% C Steel

Low-carbon steel (0.2 mass%) samples were austenitized and quenched at a cooling rate of 10°C/s under GPa level high pressure. The morphology, lattice constant, order degree C atom distribution high-pressure quenching martensite characterised analyzed by TEM, EBSD, XRD, Mössbauer. Besides, the transformation characteristics strengthening mechanisms discussed. results show that microstructure 0.2 mass% is fine hierarchical lath with almost no residual austenite, its laths mostly follow {112} <111> twin relationship, indicating self-accommodation effect among variants. Compared to atmospheric pressure, carbon increases in martensite, meanwhile tetragonality (c/a) from 1.009 pressure 1.012 4 GPa. significant promotion hardness subjected treatment can be ascribed large number dislocations structure, grain refinement caused boundary, solution distortion due increase for decrease constant. These findings provide new insights into mechanism, technique developed.