From brittle to ductile transition: The influence of oxygen on mechanical properties of metallic glasses
JC Zhang and XY Wang and M Li, JOURNAL OF ALLOYS AND COMPOUNDS, 876, 160023 (2021).
DOI: 10.1016/j.jallcom.2021.160023
Metallic glass is a brittle solid macroscopically but has tremendous ductility in nano and mesoscopic scales. Oxygen is generally considered to be the major culprit in causing the brittleness by inducing crystallization. Since oxygen is omnipresent in the making and applications of metallic glasses, how to avoid, and even take advantage of oxygen, becomes materials scientists' wild dream. Here we demonstrate using atomistic simulation that the brittle solid can be turned ductile in a model Al-based metallic glass with oxygen addition. There are two major underlying mechanisms found here, one is to keep the oxides in small size and the other is to preserve the free volumes in the surroundings of the oxide clusters. The relatively loosely packed neighboring regions of the nanosized oxide clusters make the glass softer and thereby improves deformability and thus ductility. The finding challenges experimentalists to explore and discover new class of glasses that are not only oxygen tolerant but beneficial in mechanical properties. (c) 2021 Elsevier B.V. All rights reserved.
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