Changes in Mechanical Properties, Structure and Phase Composition of 47CrNiMo Industrial Alloy after Aging

The development of the modern nuclear industry urges for materials capable of operating at high temperatures, high mechanical loads, and in aggressive contact environments. The 47CrNiMo alloy is advisable for nuclear reactors, as it has high resistance to plastic deformation and relaxation resistance under conditions of static and cyclic loading, low elastic hysteresis, high fatigue strength, and high corrosion resistance. The article presents the results of a study of changes in the mechanical properties, phase composition, and structures of the 47CrNiMo industrial alloy after aging. The methods of X-ray diffraction analysis, microhardness measurements, and diffraction electronic microscopy are used in the study. The dependence of microhardness on the aging time interval has been established. The ultimate strength and relative elongation of the studied samples are found to be dependent on the time of aging. The analysis of the 47CrNiMo X-ray diffraction patterns reveals the presence of Frank-Casper phase structures. A cluster model of grain boundaries is proposed on the basis of the conducted analysis.