工业纯锆的低周疲劳特性及寿命预估

通过轴向对称应变控制法对工业纯锆的低周疲劳性能进行研究,讨论了工业纯锆的循环应力-应变响应、软硬化特性、累积滞后规律、疲劳寿命以及塑性应变能的影响。结果表明：在总应变幅大于0.5%时工业纯锆均表现出循环硬化;工业纯锆疲劳寿命满足Basquin-Coffin-Manson经验关系式,其过渡寿命为1548周;利用塑性应变能对疲劳损伤进行了有效评估,总应变幅度越低,滞回曲线面积越小,即塑性应变能越低,疲劳寿命越长;疲劳断口呈现明显的疲劳辉纹特征,随总应变幅的增加疲劳辉纹的数量减小宽度增加。

Low Cycle Fatigue Properties and Predication of Fatigue Life for commercially purity zirconium

The Low cycle fatigue properties of the commercially pure zirconium (CP-Zr) were investigated by a method under axial loading controlled by symmetric strain. The characteristics of cyclic stress-strain response and hysteresis loop of CP-Zr were discussed. Cycle softening and hardening characteristics and cumulative hysteresis of the CP-Zr were analyzed and then the fatigue life was predicted. The results indicate that the CP-Zr displays cyclic hardening when the total strain amplitude is more than 0.5%. The fatigue life of CP-Zr matches Basquin-Coffin-Manson"s empirical relationship, whose transitional life is 1548 cycles. And the plastic strain energy can be suitably utilized as an essential parameter in fatigue failure model to evaluate the fatigue damage. The hysteresis loop area (i.e. the plastic strain energy) decreases with the total strain amplitude decreasing and the number of fatigue cycles increasing. The fatigue striation can be obviously observed, as the total strain amplitude increases, the number of fatigue striation decreases and the width increases.