Hydrogen Damage Behavior of GH625 Alloy in the Intermittent Ultrahigh Pressure Hydrogen Environment

The hydrogen damage behavior of GH625 alloy under saturated hydrogen charging and hydrogen cycling conditions was studied using a high-temperature and high-pressure gas-phase hydrogen charging method. The results show that when the hydrogen mass fraction in the sample reached 49 mg/kg, the elongation and cross-sectional shrinkage of GH625 alloy after hydrogen induced fracture decreased by 15.9% and 39.1%, respectively, but there was no significant high-temperature hydrogen corrosion. After hydrogen evolution treatment, most of the hydrogen in the sample could escape, and the plasticity was significantly restored. As the number of hydrogen charging and discharging cycles increased, the residual hydrogen content in the sample showed an upward trend. Tensile test results showed that the performance of GH625 alloy remained stable with fewer hydrogen charging and discharging cycles, and was not significantly affected by the number of hydrogen charging and discharging cycles.