渗透氢对 BCC 金属裂纹扩展行为的影响. (Chinese)

Effect of hydrogen permeation on crack propagation behavior of BCC metal. (English)

In the hydrogen environment, hydrogen atoms will stick to the surface of metal materials.Over time, hydrogen atoms will penetrate into the metal and take up empty Spaces.he concentration of hydrogen atoms leads to stress concentration, which ultimately further affects the mechanical behavior of the material.The mechanical response of hydrogen at crack tip is studied by molecular dynamics method.The results show that the hydrogen adsorbed at the crack tip reduces the bonding force between atoms, resulting in a decrease in the critical applied load required for local stress concentration. The material is destroyed under the condition of lower fracture strength, and the crack propagation is promoted to a great extent.The infiltration process of adsorbent hydrogen at the crack tip under applied load was observed, and hydrogen atoms would gather in the high-stress region, resulting in a decrease in the plasticity of the material.In addition, the number of hydrogen atoms infiltrating the material will reach a maximum critical value as the calculation time increases.When the applied strain increases, the maximum number of hydrogen atoms permeating the crack tip and the time to reach the critical value will increase. [ABSTRACT FROM AUTHOR]

在氢环境下, 氢原子会吸附在金属材料表面. 随着时间推移, 氢原子会渗透进入金属内部占据空隙位置. 氢原子的聚集会导致应力集中, 最终进一步影响材料的力学行为. 本文通过分子动力学方法研究氢在裂纹尖端行为的力学响应. 研究结果表明, 裂纹尖端吸附的氢降低了原子间的键合力, 导致局部应力集中所需的临界外加载荷减小；使得材料在较低的断裂强度条件下发生破坏, 并在很大程度上促进了裂纹的扩展. 模拟观察到在外加载荷下吸附氢在裂纹尖端的渗透过程, 氢原子会聚集在高应力区域, 造成材料塑性降低. 另外, 渗透进材料的氢原子数目会随着计算时间的增加达到一个最大临界值. 当施加应变增大, 裂纹尖端渗透氢原子数最大临界值和达到临界值的时间会增加. [ABSTRACT FROM AUTHOR]

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