Abstract:In this paper, the step fatigue test of CuCrZr copper alloy at 300°C and 400°C was carried out, and the cyclic plasticity behavior was studied from the aspects of cyclic strain amplitude, average strain, average strain rate and energy dissipation rate. It is found that the cyclic soft hardening characteristics of CuCrZr copper alloy and the ratchet effect are affected by the combination of temperature and cyclic stress, and the higher the temperature, the more prone to cyclic softening, and the ratchet effect is more significant. Based on the comparison between the high temperature tensile fracture energy of CuCrZr copper alloy and the total dissipative energy of high temperature ladder fatigue, both are related to temperature, so the high temperature tensile fracture energy is used as a temperature compensation parameter, and a linear damage fatigue life prediction model based on energy method is proposed, and the fatigue life of CuCrZr copper alloy is predicted. Finally, the temperature-related failure mechanism of CuCrZr copper alloy is analyzed based on fracture analysis: fatigue crack failure is prone to occur at lower temperatures, and with the increase of temperature, the ductility failure accumulated by ratchet strain is more likely.