Hydrogen embrittlement in metallic nanowires
Hydrogen embrittlement in metallic nanowires
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DOI：
10.1038/s41467-019-10035-0
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发表时间：
2019-05
影响因子：
16.6
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中科院分区：
文献类型：
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虽然氢脆已经在各种金属和合金中被观察到并被广泛研究，但对于其潜在的机制仍然存在争议，并且对纳米结构中的氢脆的基本理解几乎不存在。在这里，我们使用金属纳米线（NWs）作为一个平台，研究在纳米结构的变形和故障的位错成核占主导地位的氢脆。基于定量原位透射电子显微镜纳米力学测试和分子动力学模拟，我们报告了增强的屈服强度和过渡的故障机制从分布塑性局部颈缩在五孪晶银纳米线由于表面吸附氢的存在。原位应力松弛实验和模拟表明，所观察到的金属纳米线的脆化是由氢诱导的抑制位错成核在自由表面的纳米线。
Although hydrogen embrittlement has been observed and extensively studied in a wide variety of metals and alloys, there still exist controversies over the underlying mechanisms and a fundamental understanding of hydrogen embrittlement in nanostructures is almost non-existent. Here we use metallic nanowires (NWs) as a platform to study hydrogen embrittlement in nanostructures where deformation and failure are dominated by dislocation nucleation. Based on quantitative in-situ transmission electron microscopy nanomechanical testing and molecular dynamics simulations, we report enhanced yield strength and a transition in failure mechanism from distributed plasticity to localized necking in penta-twinned Ag NWs due to the presence of surface-adsorbed hydrogen. In-situ stress relaxation experiments and simulations reveal that the observed embrittlement in metallic nanowires is governed by the hydrogen-induced suppression of dislocation nucleation at the free surface of NWs.