Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Nat Commun. 2017 Feb 20;8:14564. doi: 10.1038/ncomms14564.
Hydrogen can facilitate the detachment of protective oxide layer off metals and alloys. The degradation is usually exacerbated at elevated temperatures in many industrial applications; however, its origin remains poorly understood. Here by heating hydrogenated aluminium inside an environmental transmission electron microscope, we show that hydrogen exposure of just a few minutes can greatly degrade the high temperature integrity of metal-oxide interface. Moreover, there exists a critical temperature of ∼150 °C, above which the growth of cavities at the metal-oxide interface reverses to shrinkage, followed by the formation of a few giant cavities. Vacancy supersaturation, activation of a long-range diffusion pathway along the detached interface and the dissociation of hydrogen-vacancy complexes are critical factors affecting this behaviour. These results enrich the understanding of hydrogen-induced interfacial failure at elevated temperatures.
氢气可以促使金属和合金的保护性氧化层剥落。在许多工业应用中，高温会使这种降解加剧；然而，其根本原因仍不清楚。本文通过在环境透射电子显微镜中对氢化铝进行加热，结果表明，仅几分钟的氢气暴露就可以大大降低金属-氧化物界面在高温下的稳定性。此外，在 150°C 左右存在一个临界温度，高于该温度，金属-氧化物界面处的空穴生长会由膨胀转变为收缩，随后形成几个巨型空穴。空位过饱和度、沿脱附界面的长程扩散途径的激活以及氢空位复合物的解离是影响这种行为的关键因素。这些结果丰富了对高温下氢致界面失效的理解。
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