Shear-banding Induced Indentation Size Effect in Metallic Glasses.
Shear-banding is commonly regarded as the "plasticity carrier" of metallic glasses (MGs), which usually causes severe strain localization and catastrophic failure if unhindered. However, through the use of the high-throughput dynamic nanoindentation technique, here we reveal that nano-scale shear-banding in different MGs evolves from a "distributed" fashion to a "localized" mode when the resultant plastic flow extends over a critical length scale. Consequently, a pronounced indentation size effect arises from the distributed shear-banding but vanishes when shear-banding becomes localized. Based on the critical length scales obtained for a variety of MGs, we unveil an intrinsic interplay between elasticity and fragility that governs the nanoscale plasticity transition in MGs. Our current findings provide a quantitative insight into the indentation size effect and transition mechanisms of nano-scale plasticity in MGs.
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P.R. China.|Centre for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong SAR, P.R. China.
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Lu
Centre for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong SAR, P.R. China.
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Sun
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P.R. China.
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Zhao
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P.R. China.
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Wang
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P.R. China.
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Pan
Centre for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong SAR, P.R. China.
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Liu
Centre for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong SAR, P.R. China.
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Yang