International Journal of Metalcasting, vol.18, no.2, pp.1523-1534, 2024 (SCI-Expanded)
The aim of this study was to investigate the effect of shallow cryogenic treatment on the mechanical properties and microstructural evolution of a Hadfield steel with a chemical composition of (Fe-12Mn-1.2C). An ingot was produced using casting technique and heat treated by austenitizing at 1050 °C for 1 h followed by rapid quenching to room temperature. Samples were cut from the heat treated ingot and divided into three sets: H (no further treatment), HD (5% deformation), and HDC (cryogenic treatment at −80 °C for 2 h after deformation). Microstructural characterizations were performed using optical microscopy, scanning electron microscopy, and transmission electron microscopy. X-ray diffraction was used to identify formed phases and carbides, as well as determine dislocation density, crystallite size, lattice strain value, and texture coefficient. The relationships between stacking faults and dislocation density were investigated, and the wear rate and friction coefficients of the samples were calculated. The results showed that cryogenic treatment and deformation caused mechanical twinning, transformed austenite into α′(BCT) martensite, changed the form of MC type carbides, and increased the dislocation density by approximately 50%. The stacking faults were more pronounced in the cryogenic treatment samples, and the strain value of planes calculated by XRD analysis was high in cryogenically treated samples. The wear rate of the HDC sample improved by about 20% compared to the H sample. These findings provide important insights into the structural changes of high manganese steels and can contribute to the development of new materials with improved properties.