13th International Conference on Fracture June 16–21, 2013, Beijing, China -4- energy, i.e., <E dc ν Γ , so that additional shear bands form and subsequently formation of a network of shear-bands induces the fragmentation failure mode of the material. 4.4 Fracture strength Considering the intrinsic heterogeneity and preexisting flaw resulted from casting, the shear band generates via the cascade of a number of individual atomic jumps around free-volume sites[15] or shear transformation zones[14, 35] under the action of a stress smaller than macro yielding stress [2, 36]. Under dynamic compression, the formation and accumulation of damage resulted from network-like multiple shear bands events, causes the materials would loose bearing load earlier, however, the materials could not bear load until the stress level achieves macroscopic yield situation under quasistatic compression. 5 Conclusion The mechanical properties of the Zr41.2Ti13.8Cu10Ni12.5Be22.5 bulk metallic glass were investigated under uniaxial compression at strain rates from 10-4s-1 to 103s-1. The compressive failure process consists of typical shear fracture and fragmentation fracture, depending on the loading strain rate. The failure mode changes dramatically as loading strain rate is increased into high strain rate range. The different modes indicate that different mechanisms control fracture. Considering the balance between the energy dissipation within shear band and the energy residing within the vicinity of the shear band released to fuel shear localization, one dominant shear band controls the failure process at low strain rate, however, that is controlled by network-like multiple shear bands at high strain rate. The relationship between the failure mode and fracture strength is briefly discussed. Acknowledgments Financial support is from National Key Basic Research Program of China (Grant No. 2012CB937500), the NSFC (Grants Nos. 11202221, 11132011, 11002144 and 11021262), and the National Natural Science Foundation of China-NSAF (Grant No: 109761010). References [1] L.H. Dai, Shear Banding in Bulk Metallic Glasses. in: Y.L. Bai, B.Dodd (2nd Eds.) Adiabatic Shear Localization : Frontiers and Advances. Elsevier, 2012, pp. 311—361 [2] T. Mukai, T.G. Nieh, Y. Kawamura, A. Inoue, K. Higashi, Effect of strain rate on compressive behavior of a Pd40Ni40P20 bulk metallic glass. Intermetallics, 10 (2002) 11-121071-1077. [3] Y. Yang, J.C. Ye, J. Lu, Y.F. Gao, P.K. Liaw, Metallic Glasses: Gaining Plasticity for Microsystems. Jom, 62 (2010) 293-98. [4] M. Ashby, A. Greer, Metallic glasses as structural materials. Scripta Mater, 54 (2006) 3321-326. [5] C. Schuh, T. Hufnagel, U. Ramamurty, Mechanical behavior of amorphous alloys. Acta Mater, 55 (2007) 124067-4109. [6] L. Liu, L. Dai, Y. Bai, B. Wei, Initiation and propagation of shear bands in Zr-based bulk metallic glass under quasi-static and dynamic shear loadings. J Non-Cryst Solids, 351 (2005) 40-423259-3270. [7] L.H. Dai, Y.L. Bai, Basic mechanical behaviors and mechanics of shear banding in BMGs. Int J Impact Eng, 35 (2008) 8704-716. [8] Y. Xue, H. Cai, L. Wang, F. Wang, H. Zhang, Effect of loading rate on failure in Zr-based bulk
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