Multiple Cracks Initiation and Propagation Behavior of Stainless Steel in High Temperature Water Environment
Multiple Cracks Initiation and Propagation Behavior of Stainless Steel in High Temperature Water Environment
复制标题
高温水环境下不锈钢多重裂纹萌生及扩展行为
DOI：
10.3323/jcorr1991.50.57
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
N. Totsuka
中科院分区：
文献类型：
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作者：
M. Kamaya;G. Chiba;N. Nakajima;N. Totsuka
环境辅助裂纹萌生行为受外加应力和环境因素的影响很大，如水温、含杂质等。另一方面，裂纹萌生行为也会影响裂纹的扩展。这种影响的一个典型例子可以观察到多个裂纹的干涉效应，例如接近的裂纹尖端的合并或相邻裂纹松弛区的停滞现象。了解裂纹萌生对裂纹扩展行为的影响，对于预测构件的寿命是非常重要的，因为构件容易产生大量的裂纹。本研究旨在揭示裂纹萌生行为及其对扩展的影响。首先，为了评价外加应力对敏化不锈钢裂纹萌生行为的影响，在高温水环境中进行了恒定电位为ECP+50 mV和ECP+150 mV的四点弯曲试验。其次，建立了基于实验结果的裂纹萌生与扩展仿真模型，利用有限元方法对多个裂纹的干涉效应进行了评估。利用该模型研究了裂纹萌生与扩展之间的关系。从模型中可以看出，随着裂纹数量的增加，裂纹扩展速度加快，寿命降低。
Environmentally assisted crack initiation behavior is greatly affected by applied stress and environmental factors, such as water temperature, contained impurities and so on. On the other hand, crack initiation behavior also influences crack propagation. A typical example of this influence can be observed as the interference effects of multiple cracks, such as the coalescence of approaching crack tips or the arrest phenomena in the relaxation zone of an adjacent crack. To understand these effects of crack initiation on crack propagation behavior is very important to predict the lifetime of components, in which quite a few cracks tend to occur. This study aimed at revealing the crack initiation behavior and the influence of this behavior on propagation. At first, to evaluate the effect of applied stress on crack initiation behavior, sensitized stainless steel was subjected to a four-point bending test in a high temperature water environment at the constant potentials of ECP +50mV and ECP +150mV. Secondly, a crack initiation and growth simulation model was developed, in which the interference effect of multiple cracks is evaluated by the finite element method, based on the experimental results. Using this model, the relationship between crack initiation and propagation was studied. From the model, it was revealed that the increasing number of the cracks accelerates crack propagation and reduces life.