Effect of phase-transformation hardening of austenite on the crystal structure of martensite at cryogenic temperatures

Single-crystal specimens of 50N25 steel were examined by the X-ray diffraction method to study low-temperature changes in the crystal structure of martensite freshly formed in austenite subject to γ-α-γ transitions. It was shown that, at cryogenic temperatures, the decomposition of transformation-hardened martensite was superimposed on the relaxation of coherent stresses and the ordering of carbon atoms in the interstices of the crystal lattice.