title: In situ study of the initiation of hydrogen bubbles at the aluminium metal/oxide interface.
abstract: The presence of excess hydrogen at the interface between a metal substrate and a protective oxide can cause blistering and spallation of the scale. However, it remains unclear how nanoscale bubbles manage to reach the critical size in the first place. Here, we perform in situ environmental transmission electron microscopy experiments of the aluminium metal/oxide interface under hydrogen exposure. It is found that once the interface is weakened by hydrogen segregation, surface diffusion of Al atoms initiates the formation of faceted cavities on the metal side, driven by Wulff reconstruction. The morphology and growth rate of these cavities are highly sensitive to the crystallographic orientation of the aluminium substrate. Once the cavities grow to a critical size, the internal gas pressure can become great enough to blister the oxide layer. Our findings have implications for understanding hydrogen damage of interfaces.
authors.affiliation: Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) &Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: De-Gang
authors.initials: DG
authors.lastname: Xie
authors.affiliation: Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) &Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Zhang-Jie
authors.initials: ZJ
authors.lastname: Wang
authors.affiliation: Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) &Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Sun
authors.affiliation: Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) &Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.|Department of Nuclear Science and Engineering, Cambridge, Massachusetts 02139, USA.|Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Ju
authors.initials: J
authors.lastname: Li
authors.affiliation: Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) &Hysitron Applied Research Center in China (HARCC), 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.
authors.forename: Evan
authors.initials: E
authors.lastname: Ma
authors.affiliation: Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) &Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Zhi-Wei
authors.initials: ZW
authors.lastname: Shan