Relationship between hydrogen-assisted crack propagation rate and the corresponding crack path in AISI 4340 steel
Relationship between hydrogen-assisted crack propagation rate and the corresponding crack path in AISI 4340 steel
复制标题
DOI：
10.1002/srin.199000371
复制
发表时间：
1990-09
期刊：
影响因子：
--
通讯作者：
Su-Ii Pyun;H. Lie
中科院分区：
文献类型：
--
作者：
Su-Ii Pyun;H. Lie
在本研究中，氢辅助（HA）裂纹扩展速率和相应的断裂模式之间的关系在AISI 4340钢已阐明与临界氢浓度的概念。氢辅助裂纹扩展速率和相应的断裂表面形态是从双悬臂梁（DCB）试样中确定的，作为氢压力和温度的函数。随着氢压的降低，氢辅助裂纹扩展开始所需的阈值应力强度因子增加，II阶段（平台）裂纹扩展速率降低。第II阶段裂纹扩展的动力学表明存在实质性差异，即，在两个调查的低温和高温区，分别为积极和消极的反应。断口分析表明，微孔聚结模式的数量增加导致裂纹扩展速率减慢。根据临界应力或应变和临界氢浓度概念，讨论了观察到的裂纹扩展速率和相应的断裂模式随氢压力和温度的变化。
In the present investigation, relationship between hydrogen‐assisted (HA) crack propagation rate and the corresponding fracture mode in AISI 4340 steel has been elucidated with critical hydrogen concentration concept. Hydrogen assisted crack‐propagation rate and the corresponding fracture surface morphology were determined from double cantilever beam (DCB) specimens as a function of hydrogen pressure and temperature. As hydrogen pressure decreased, threshold stress intensity factor necessary for the onset of hydrogen‐assisted crack propagation increased and the stage II (plateau) crack‐propagation rate decreased. The kinetics of stage II crack propagation indicated substantial difference, i.e., positive and negative responses in the two investigated low and high temperature regions, respectively. Fractographic analysis showed that increased amounts of the microvoid coalescence mode resulted in slower crack‐propagation rates. The observed changes in crack‐propagation rate and the corresponding fracture mode with hydrogen pressure and temperature are discussed in terms of critical stress or strain and critical hydrogen concentration concepts.