Shear-band cavities and strain hardening in a metallic glass revealed with phase-contrast x-ray tomography

SCRIPTA MATERIALIA

卷:170

Article

Liu, C.^1,2  Das, A.^1,2  Wang, W.^1,2  Kuchemann, S.^1,2  Kenesei, P.³  Maass, R.^1,2 

[1] Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA

[2] Univ Illinois, Frederick Seitz Mat Res Lab, Urbana, IL 61801 USA

[3] Argonne Natl Lab, Adv Photon Source, 9700 South Cass Ave, Argonne, IL 60439 USA

关键词: Metallic glass;    Shear bands;    Cavities;    Fracture;    X-ray tomography;   

DOI  :  10.1016/j.scriptamat.2019.05.021

来源: Elsevier

【 摘 要 】

Using high-energy x-ray tomography we show that deformed Zr-based metallic-glass samples contain large amounts of shear-band cavities (internal cracks). Since the investigated samples were unloaded prior to fracture, the three-dimensionally reconstructed samples can be used to determine the true load-bearing area, which leads to the conclusion that the samples have hardened considerably during deformation. We propose how such apparent strain hardening can be caused by a change in friction condition between the detached surfaces instead of searching for an intrinsic hardening mechanism. These results indicate the importance of knowing the true load-bearing area for correct flow-stress determinations of metallic glasses. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

【 授权许可】

Free