Low‐Cycle Fatigue Behavior and Life Prediction of Copper Busbar

Copper has many applications especially in rotor parts subjected to fatigue loading. From them, a typical copper busbar is chosen to mainly investigate the low‐cycle fatigue (LCF) behaviors, fracture morphologies, dislocation patterns and crack initiation mechanism. It is found that with total strain amplitude increasing, cyclic softening appears in all the samples; the fatigue crack initiation sites transform mainly from slip bands to grain boundaries; the dislocation spacing of the post‐fatigue samples decreases; by comparison, the Basquin–Manson–Coffin and the simplified hysteresis energy relations are relatively simple and accurate methods to predict fatigue life. Finally, the LCF properties of the coppers with different grain sizes prepared by different technologies are compared and optimized.