Vacuum retarding and air accelerating effect on the high-cycle and very-high-cycle fatigue behavior of a ZK60 magnesium alloy
Vacuum retarding and air accelerating effect on the high-cycle and very-high-cycle fatigue behavior of a ZK60 magnesium alloy
复制标题
真空缓速和空气加速对ZK60镁合金高周和甚高周疲劳行为的影响
DOI：
10.1016/j.matdes.2020.109310
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发表时间：
2021-01-15
影响因子：
8.4
通讯作者：
Wang, Qingyuan
中科院分区：
文献类型：
--
作者：
Liu, Yongjie;Chen, Yao;Wang, Qingyuan
早期人们怀疑细晶区（FGA）的超慢裂纹扩展可能对内部真空环境敏感。换句话说，在非常高的循环制度的疲劳失效可能与内部真空的环境。由于镁合金对环境影响较为敏感，因此本研究选择镁合金作为研究载体。对镁合金在大气和真空环境下进行了对比研究，真空加载环境为研究可能的环境效应提供了有价值的参考。结果表明，在不同加载环境下，裂纹萌生处的塑性变形机制基本一致。然而，不同的载荷环境不仅改变了疲劳寿命，而且改变了失效模式。在较高的应力水平下，表面失效在空气加载环境中占主导地位，而内部失效在真空加载环境中占主导地位，并呈现较长的疲劳寿命。认为真空加载环境下的失效模式主要受临界晶粒的影响，而空气加载环境下的失效模式主要受表面空气加速效应与临界晶粒的竞争影响。疲劳寿命主要受内部真空阻滞效应和表面空气加速效应的影响。(C)2020年，任作家。爱思唯尔有限公司出版
It is suspected early that the ultra-slow crack propagation in fine-granular-area (FGA) may be sensitive to the internal vacuum-like environment. In other words, fatigue failure in the very-high-cycle regime may be related to the internal vacuum-like environment. Since magnesium alloy is more susceptible to the environmental effect, it is selected as the research carrier in this study. A magnesium alloy is investigated in ambient air and vacuum environments comparatively, and the vacuum loading environment offers a valuable reference to investigate the possible environmental effect. The results show that plastic de formation mechanism in different loading environments keeps the same at crack initiation site. However, the different loading environments not only change the fatigue life, but also the failure mode. At higher stress levels, surface failure dominates in air loading environment, whereas internal failure dominates in vacuum loading environment and presents longer fatigue life. It is considered that failure mode in vacuum loading environment is mainly affected by the critical grains, whereas that in air loading environment is mainly affected by the competition between the surface air acceleration effect and the critical grains. Fatigue life is mainly affected by the internal vacuum retarding effect and the surface air accelerating effect. (C) 2020 The Authors. Published by Elsevier Ltd.