Saturation effect of creep-fatigue cyclic-life for Nickel-based superalloy DZ445 under long-term tensile dwell periods at 900 °C
Saturation effect of creep-fatigue cyclic-life for Nickel-based superalloy DZ445 under long-term tensile dwell periods at 900 °C
复制标题
DOI：
10.1016/j.jmrt.2022.06.073
复制
发表时间：
2022-06
期刊：
影响因子：
--
通讯作者：
Shunran Zhang;W. Ren;B. Ding;Y. Zhong;Xiaotan Yuan;T. Zheng;Z. Shen;Yifeng Guo;Qiang Li;Chunmei Liu;J. Peng;J. Brnić;Yanfei Gao;P. Liaw
中科院分区：
文献类型：
--
作者：
Shunran Zhang;W. Ren;B. Ding;Y. Zhong;Xiaotan Yuan;T. Zheng;Z. Shen;Yifeng Guo;Qiang Li;Chunmei Liu;J. Peng;J. Brnić;Yanfei Gao;P. Liaw
这项研究确定了 DZ445 高温合金的蠕变疲劳循环寿命 (Nf) 饱和效应，在 900 °C 下停留时间为 16-128 分钟，总应变范围为 1.6%。当保压时间超过8分钟时，包括最大应力响应、磁滞回线、塑性应变范围和特征周期应力松弛量在内的机械响应也随着保压时间逐渐饱和。 Nf 饱和效应也反映在蠕变和延性主导的断裂模式中。这一关键现象与γˊ析出中a/2[101]超位错达到动态平衡与位错网络的形成密切相关。而断裂时间随着保压时间的增加而不断增加，当循环寿命饱和时，可以更好地作为评价指标。 Nf饱和效应不仅可以降低长驻留时间试验的成本，而且可以为蠕变疲劳安全设计提供指导。
This investigation determined the creep-fatigue cyclic-life (Nf) saturation effect for the DZ445 superalloy with 16–128 min dwell time at 900 °C and total strain range of 1.6%. When the dwell time exceeds 8 min, the mechanical response including maximum stress response, hysteresis loop, plastic strain range, and stress relaxation amount at characteristic cycle are also saturated with dwell time gradually. The Nfsaturation effect is also reflected in the creep- and ductile-dominated fracture modes. This critical phenomenon is closely related to the dynamic equilibrium reached between the superdislocations of a/2[101] in γˊ precipitation and the formation of the dislocation networks. While the rupture time is increased continuously with dwell time, which could be better used as an evaluation index when the cyclic life is saturated. The Nfsaturation effect can not only reduce the cost of tests with long-dwell time, but also provide the guidance for creep-fatigue safety design.