Numerical simulation of the effects of residual stress on the concentration of hydrogen around a crack tip
Numerical simulation of the effects of residual stress on the concentration of hydrogen around a crack tip
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DOI：
10.1016/j.surfcoat.2011.12.018
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发表时间：
2012-02
影响因子：
5.4
通讯作者：
O. Takakuwa;M. Nishikawa;H. Soyama
中科院分区：
文献类型：
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作者：
O. Takakuwa;M. Nishikawa;H. Soyama
在这项研究中，我们使用有限元分析来显示疲劳过程后塑性变形材料裂纹尖端周围的残余应力如何影响氢浓度。经过9周疲劳过程后，在最高施加疲劳应力下进行了氢扩散分析。这表明氢侵入裂纹表面并扩散到材料中。靠近裂纹尖端的氢离子浓度较高，其行为受材料中残余应力的影响较大。拉伸残余应力加速了氢的侵入，增加了氢的浓度，而压缩残余应力模拟了喷丸诱导的应力，明显抑制了氢的侵入。这是由于残余应力对裂纹尖端周围静水应力的影响，而静水应力是影响氢扩散行为的主要因素。强化是一种表面处理，用于引入压缩残余应力，以提高材料的机械性能，例如抗应力腐蚀开裂和疲劳强度，因此可以抑制氢引起的脆化。
For this study we used finite element analysis to show how the residual stress affects the hydrogen concentration around a crack tip in a plastically deformable material after a fatigue process. Following a 9cycle fatigue process, hydrogen diffusion analysis was carried out at the highest applied fatigue stress. This showed hydrogen invading the crack surface and diffusing into the material. The concentration of hydrogen was higher close to the crack tip and its behavior was largely affected by the residual stress in the material. Tensile residual stress accelerated the hydrogen invasion and increased its concentration, while compressive residual stress simulated as the stress induced by peening clearly suppressed them. This is due to the affect the residual stress has on the hydrostatic stress around the crack tip which is a dominant factor in the hydrogen diffusion behavior. Peening, which is a surface treatment used to introduce compressive residual stress to enhance the mechanical properties of a material, such as its resistance to stress corrosion cracking and its fatigue strength, may, therefore, suppress the embrittlement caused by hydrogen.