Hydrogen embrittlement susceptibility of a Ni-16Mo-7Cr base superalloy
Hydrogen embrittlement susceptibility of a Ni-16Mo-7Cr base superalloy
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Ni-16Mo-7Cr基高温合金的氢脆敏感性
DOI：
10.1016/j.msea.2018.07.077
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发表时间：
2018
期刊：
影响因子：
6.4
通讯作者：
Zhou X. T.
中科院分区：
文献类型：
--
作者：
Han Fenfen;He Suixia;Liu Min;Zhou X. T.
研究了Ni-16Mo-7Cr基高温合金在不同预充氢状态下的氢脆敏感性。对拉伸试验后的预充氢合金进行了详细的电镜表征，以了解氢辅助开裂的机理。结果表明：随着预充氢时间的延长，合金的抗拉强度显著降低，而屈服强度一直保持稳定；断口形貌结合扫描电镜ECCI分析表明，在氢存在的情况下，裂纹主要沿晶界扩展，少数裂纹沿平面位错滑移带扩展，特别是沿非平行位错滑移带的交叉处扩展。提出了Ni-16Mo-7Cr基高温合金的氢脆机制：氢与位错相互作用导致的纳米空洞的聚并扩大，导致裂纹沿晶界萌生和扩展，进而导致合金的晶间断裂。
This study investigated the hydrogen embrittlement sensitivity of a Ni-16Mo-7Cr base superalloy under different hydrogen pre-charging states. Detailed electromicroscopy characterization has been employed on the hydrogen pre-charged alloy after tensile testing to understand the mechanism of hydrogen-assisted cracking. The results show that the tensile strength of the alloy is remarkably decreased with the increasing of hydrogen pre-charging time, whereas the yield strength remains stable all the time. The fractographic study combined with ECCI analysis by Scanning Electron Microscopy demonstrates that the cracks propagated predominantly along the grain boundary in the presence of hydrogen, and a few can propagate along planar dislocation slip bands (DSBs) especially along the intersections between nonparallel DSBs. The proposed hydrogen embrittlement mechanism for the Ni-16Mo-7Cr base superalloy is that the coalescence and widening of the nano-voids, which are resulted from the interaction between the hydrogen and dislocations, cause the crack initiation and propagation along the grain boundary, and further cause the alloy intergranular fracture.