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Explication of the degradation mechanism of the strength of heat-resistant alloys under random loading at elevated temperatures and the establishment of the prediction method of their lifetime

高温随机载荷下耐热合金强度退化机理的解释及寿命预测方法的建立

基本信息

批准号：
21F50350
负责人：
三浦英生
金额：
$ 0.64万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for JSPS Fellows
财政年份：
2021
资助国家：
日本
起止时间：
2021-11-18 至 2023-03-31
项目状态：
已结题

项目摘要

The main objectives of this research are 1) Clarification of the acceleration mechanism of the degradation of materials under creep-fatigue loading at elevated temperatures, and 2) Establishment of the quantitative evaluation method of the damage of the materials under random load conditions. Original small dumbbell-shape specimens were manufactured for both the observation of the degradation process under the distribution of the applied load and the direct observation of the change of the local crystallinity of the alloy in a scanning electron microscope. The degradation process of the crystallinity of the representative heat-resistant alloy, Ni-base superalloy, under creep-fatigue loading at elevated temperatures was monitored continuously by using our original intermittent micro tensile test method with electron microscopy. The degradation process of the crystallinity and strength of the material was continuously observed, and it was explicated by applying the modified Arrhenius equation by considering the effect of mechanical stress on the local decrease in the activation energy of atomic diffusion. it was also found that the accumulation of vacancies and dislocations was accelerated only around grain boundaries and thus, the initiation time of intergranular cracking became shorter when the strain rate during loading and unloading became faster. The main reason for the acceleration was found to be the activation of viscoelasticity of the alloy at the elevated temperature.

本研究的主要目的是：1）阐明材料在高温蠕变疲劳载荷下加速退化的机理; 2）建立随机载荷条件下材料损伤的定量评估方法。制作了原始哑铃形小试样，在扫描电子显微镜下观察了合金在载荷分布下的降解过程，并直接观察了合金局部结晶度的变化。采用我们独创的带电子显微镜的间歇式微拉伸试验方法，对典型耐热合金镍基高温合金在高温蠕变疲劳载荷下的结晶度退化过程进行了连续监测。连续观察了材料结晶度和强度的退化过程，并考虑了机械应力对原子扩散激活能局部下降的影响，应用修正后的Arcidius方程对退化过程进行了解释。研究还发现，空位和位错的积累仅在晶界附近加速，因此，当加载和卸载期间的应变速率变得更快时，晶间裂纹的起始时间变得更短。加速的主要原因被认为是在高温下的合金的粘弹性激活。

项目成果

期刊论文数量（16）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

A crystal plasticity-based approach for creep-fatigue life prediction and damage evaluation in a nickel-based superalloy

DOI：
10.1016/j.ijfatigue.2020.106031
发表时间：
2021-02-01
期刊：
INTERNATIONAL JOURNAL OF FATIGUE
影响因子：
6
作者：
Li, Kai-Shang;Wang, Run-Zi;Miura, Hideo
通讯作者：
Miura, Hideo

Creep-fatigue life design and reliability analysis in high-temperature components

高温部件的蠕变疲劳寿命设计和可靠性分析

DOI：
发表时间：
2021
期刊：
影响因子：
0
作者：
Run-Zi Wang;Lv-Y iCheng;Shun-Peng Zhu;Peng-Cheng Zhao;Hideo Miura;Xian-Cheng Zhang;Shan-TungTu;Runzi Wang;Run-Zi Wang;Run-Zi Wang
通讯作者：
Run-Zi Wang

東北大学　三浦・鈴木研究室

东北大学三浦/铃木实验室