Fracture Toughness and Hydrogen‐Assisted Crack Growth in Engineering Alloys
Fracture Toughness and Hydrogen‐Assisted Crack Growth in Engineering Alloys
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工程合金的断裂韧性和氢辅助裂纹扩展
DOI：
10.1002/9781118803363.ch36
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
J. Knott
中科院分区：
文献类型：
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作者：
J. Knott
本文首先解释了宏观断裂韧性值如何与纳米尺度断裂模型相协调，将宏观变形视为前兆功，并考虑微观尺度上的局部断裂事件。然后讨论了氢对这些局部过程的影响，包括穿晶解理、晶间断裂、微孔洞连接和氢化物裂纹的形成。本文描述了在含氢低碳钢中“准解理”扩展的观察结果，并注意了裂纹扩展的晶体学。氢的主要作用被认为是它对内聚力的影响。压力本身的影响被认为是不太重要的。类似的考虑也适用于晶间断裂，氢对快剪切断裂的影响归因于颗粒/基体界面凝聚力的减弱。最后，对氢化物辅助开裂进行了评述。
This paper explains first how macroscopic values of fracture toughness can be reconciled with nano-scale models of fracture, by treating the macroscopic deformation as precursor work and considering local fracture events at the microscale. The effect of hydrogen on these local processes is then discussed with reference to transgranular cleavage, intergranular fracture, micro-void linkage and the formation of hydride cracks.Observations of" quasi-cleavage" propagation in hydrogen-charged mild steel are described, with attention being paid to the crystallography of crack advance. The main role of hydrogen is considered to be its effect on cohesion. Effects of pressure alone are held to be of less significance. Similar considerations hold for intergranular fractures and the effect of hydrogen on fast shear fracture is attributed to the weakening of particle/matrix interfacial cohesion. Finally, comments are made on hydride-assisted cracking.