Shear fracture and fragmentation mechanisms of bulk metallic glasses

Abstract

Zr- and Co-based bulk metallic glasses display completely different failure modes under compressive loading. Zr-based metallic glasses always fail in a pure shear mode, whereas Co-based metallic glasses often break into small particles or powder, exhibiting a fragmentation mode. The difference in the failure modes for the two glassy alloys indicates that different mechanisms control the fracture processes, which can be described by a combined effect of surface energy γ, cleavage strength σ₀, fragmentation coefficient F_n and fracture mode factor α = τ₀/σ₀.

Acknowledgements

We thank J. Das, W. Gao, E. Ma, X. F. Pan, M. Stoica, H. H. Su, J. Xu and Y. K. Xu for technical assistance and stimulating discussions. This work was financially supported by the National Natural Science Foundation of China (NSFC) under grant Nos. 50401019, 50323009 and 50625241, and the ‘Hundred of Talents Project’ by the Chinese Academy of Sciences. Additional support provided by the European Union within the framework of the Research Training Network on ‘ductile bulk metallic glass composites’ (MRTN-CT-2003-504692) is also gratefully acknowledged.