Zr-4合金低周疲劳特性研究

Study on Low Cycle Fatigue Behavior of Zircaloy-4 Plate

研究了再结晶态Zr-4合金板材在室温和400℃下的低周疲劳特性。Zr-4合金在室温下的循环变形行为与应变幅有关,当应变幅小于0.8％时,表现为循环软化;应变幅大于0.8％时,表现为循环硬化。在400℃下均表现为循环硬化。合金在室温和400℃下,均遵循Coffin-Manson关系。在低应变幅下,室温的低周疲劳性能明显优于400℃下的低周疲劳性能,随着应变幅的增加,两者寿命趋于接近。用扫描电子显微镜观察分析了合金在室温和400℃下的疲劳断口特征。

Low cycle fatigue (LCF) behavior of a recrystallized zircaloy-4 plate were investigated using symmetric tension-compression test at room temperature and 400 ℃ , respectively. The results indicate that alloy displays cyclic softening at the strain amplitude lower than 0. 8% and cyclic hardening at strain amplitude higher than 0. 8% at room temperature, and cyclic hardening at the total strain range at 400 ℃. The curves of fatigue lifetime vs. cyclic plastic strain range show that the alloy obeys Coffin-Manson relationship, and has better LCF property at room temperature than 400 ℃. Finally, SEM was used to investigate the fractural characterization.