The effect of crack tip environment on crack growth behaviour of a low alloy steel at cathodic potentials in artificial seawater
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2020年第19期
论文作者：Yong Li Zhiyong Liu Endian Fan Zhongyu Cui Jinbin Zhao
文章页码：119 - 131
摘 要：The environment at crack tip and its effect on the crack growth behaviour of low alloy steel-E690 steel were studied at cathodic potentials in artificial seawater. The results showed that the micro environment at crack tip and crack growth behaviour were related to the electrochemical reactions at crack tip, which were affected by the stress state and applied potentials. The crack tip environment was acidified under cyclic loading, resulting from the crack tip anodic dissolution reaction and corresponding hydrolysis reaction. Because of the hydrogen evolution and the inhibited anodic dissolution inside the crack, the crack tip p H increases as the cathodic potential decreases. The effect of cathodic potentials on the electrochemical reactions caused the variation of the hydrogen content, which influenced the crack growth rate because the crack growth behaviour was controlled by hydrogen embrittlement mechanism. This resulted in a fact that with the negative decrease of potential, the crack growth rate first decreased and then increased,with the minimum rate at-0.75 V. And the crack growth path exhibited transgranular fracture.
Yong Li1，Zhiyong Liu1,2，Endian Fan1，Zhongyu Cui3，Jinbin Zhao1,4
1. Corrosion and Protection Center, University of Science and Technology Beijing2. Shandong Key Laboratory of Corrosion Science, Institute of Oceanology, Chinese Academy of Sciences3. School of Materials Science and Engineering, Ocean University of China4. Jiangsu Key Laboratory for Premium Steel Material, Nanjing Iron & Steel United Co., Ltd.
摘 要：The environment at crack tip and its effect on the crack growth behaviour of low alloy steel-E690 steel were studied at cathodic potentials in artificial seawater. The results showed that the micro environment at crack tip and crack growth behaviour were related to the electrochemical reactions at crack tip, which were affected by the stress state and applied potentials. The crack tip environment was acidified under cyclic loading, resulting from the crack tip anodic dissolution reaction and corresponding hydrolysis reaction. Because of the hydrogen evolution and the inhibited anodic dissolution inside the crack, the crack tip p H increases as the cathodic potential decreases. The effect of cathodic potentials on the electrochemical reactions caused the variation of the hydrogen content, which influenced the crack growth rate because the crack growth behaviour was controlled by hydrogen embrittlement mechanism. This resulted in a fact that with the negative decrease of potential, the crack growth rate first decreased and then increased,with the minimum rate at-0.75 V. And the crack growth path exhibited transgranular fracture.
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