Intrinsic shear strength of metallic glass
YQ Cheng and E Ma, ACTA MATERIALIA, 59, 1800-1807 (2011).
The intrinsic (ideal) strength has been extensively studied for crystalline alloys, but remains largely unsettled for metallic glasses. This study, by combining computer simulations and the cooperative shear model (Johnson and Samwer, 2005 12), found that, at the athermal limit, the yield strain of metallic glass can be as high as similar to 10% in pure shear, and the corresponding ideal shear strength is G/10 (where G is the shear modulus), at which shear bands nucleate homogeneously in the metallic glass. The athermal extrapolation of the measured strength in conventional loading tests is much lower, owing to the unavoidable imperfections in realistic samples, where shear band nucleation is always heterogeneous and facilitated by stress concentrators. The two scenarios have different temperature dependence and merge at elevated temperatures, when the mode of yielding eventually changes from strain localization to homogeneous flow. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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