Surface terraces in pure tungsten formed by high temperature oxidation. (December 2019)

• Record Type: Journal Article
• Authors: Yu, Hongbing; Das, Suchandrima; Liu, Junliang; Hess, Jason; Hofmann, Felix
• Is Part Of: Scripta materialia. Number 173(2019)
• Page Start: 110
• Page End: 114
• Publication Date: 2019-12
• Subjects: Surface terraces -- Tungsten -- Oxidation -- Orientation-dependence; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2019.08.007
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: We observe large-scale surface terraces in tungsten oxidised at high temperature and in high vacuum. Their formation is highly dependent on crystal orientation, with only {111} grains showing prominent terraces. Terrace facets are aligned with {100} crystallographic planes, leading to an increase in total surface energy, making a diffusion-driven formation mechanism unlikely. Instead we hypothesize that preferential oxidation of {100} crystal planes controls terrace formation. Grain height profiles after oxidation and the morphology of samples heat treated with limited oxygen supply are consistent with this hypothesis. Our observations have important implications for the use of tungsten in extreme environments. Graphical abstract: Unlabelled Image