Effect of HIP temperature on microstructure and low cycle fatigue strength of CuCrZr alloy

Nishi, Hiroshi; Enoeda, Mikio

In order to investigate the effect of the HIP cycle temperatures on the metallurgic degradation and the mechanical properties, especially on the fatigue behavior, observations of the microstructure, tensile test, Charpy impact test and low cycle fatigue test are performed for various heat treated CuCrZr alloys, which were solution-annealed followed by water-quenched and aged state and CuCrZr with simulated HIP cycle at temperatures of 980, 1045 C. Grain growth remarkably occurred on 1045 CHIP CuCrZr, though slightly on 980 C HIP CuCrZr. Metallurgic degradation such as voids was not obviously found by optical and SEM observation. There were coarse precipitates in all the CuCrZr. The coarse precipitates did not go easily into re-solution at temperature of 980 C. The low cycle fatigue strength of 1045 CHIP CuCrZr was lower than that of other CuCrZr. The degradation is attributed to the cracks which were caused by metallurgic degradation in the heat cycle.