The Influence of Gaseous Hydrogen on the Properties of Heat-Resistant Nickel-Cobalt Alloy Under Static and Cyclic Loading

The influence of hydrogen at pressures up to 65 MPa on the strength, plasticity, and low-cycle fatigue life of the KhN60KMUBTF alloy samples at temperatures of 293–1073 K, short-term tensile rates of 0.1–100 mm/min, cyclic bending frequencies and amplitudes of 50 Hz and 0.8 and 1.6%, respectively, was studied. The properties of the samples decrease with the increase of hydrogen pressure, decrease of loading rate, and amplitude in hydrogen. The ultimate strength and true fracture stress of smooth samples decrease in 1.5 times, and the ultimate strength of samples with the stress concentrator decreases by more than two times under the maximum embrittlement at a hydrogen pressure of 65 MPa and the tensile rate of 0.1 mm/min. In this case, the brittle intergranular fracture occurs and plastic deformation of the samples is almost completely absent. With increasing temperature the influence of hydrogen decreases, but remains noticeable at 1073 K.