Effects of geometric factors and shear band patterns on notch sensitivity in bulk metallic glasses

Abstract Recent experiments in notched bulk metallic glasses have found reduced, or insensitive, or improved strengths, while in many of these cases the ductile strain prior to final failure is enhanced. First, although the inverse notch effect is explained by a shift from shear localization to cavitation failure, it is suggested in this work that the synergistic effect between cohesive fracture at the notched area and shear bands emanating from the notch roots may extend the parametric space for the notch insensitive behavior. Second, the dependence of shear band patterns on notch geometric factors is determined by the Rudnicki-Rice theory and the free-volume-based finite element simulations. These results suggest conditions for shear band multiplication to take place and for the shear-localization-induced failure to be delayed.

[1]  Yanfei Gao.  Deformation fields near a steady fatigue crack with anisotropic plasticity , 2016 .

[2]  Reinhold H. Dauskardt,et al.  Mean stress effects on flow localization and failure in a bulk metallic glass , 2001 .

[3]  Frans Spaepen,et al.  A microscopic mechanism for steady state inhomogeneous flow in metallic glasses , 1977 .

[4]  Yanfei Gao,et al.  A simple technique for avoiding convergence problems in finite element simulations of crack nucleation and growth on cohesive interfaces , 2004 .

[5]  L. Dai,et al.  Nature of crack-tip plastic zone in metallic glasses , 2016 .

[6]  S. Fu,et al.  Cryogenic-temperature-induced transition from shear to dilatational failure in metallic glasses , 2014 .

[7]  T. P. G. Thamburaja.  Length scale effects on the shear localization process in metallic glasses: A theoretical and computational study , 2011 .

[8]  U. Ramamurty,et al.  Mode I crack tip fields in amorphous materials with application to metallic glasses , 2007 .

[9]  J. Rice,et al.  CONDITIONS FOR THE LOCALIZATION OF DEFORMATION IN PRESSURE-SENSITIVE DILATANT MATERIALS , 1975 .

[10]  Y. Gao,et al.  An implicit finite element method for simulating inhomogeneous deformation and shear bands of amorphous alloys based on the free-volume model , 2006 .

[11]  Yunpeng Jiang.  Numerical study of the notch effect on the malleability of bulk metallic glasses based on the free-volume theory , 2016 .

[12]  R. Narasimhan,et al.  Notch sensitivity in nanoscale metallic glass specimens: Insights from continuum simulations , 2016 .

[13]  Zhigang Suo,et al.  Remarks on Crack-Bridging Concepts , 1992 .

[14]  J. Hutchinson,et al.  The relation between crack growth resistance and fracture process parameters in elastic-plastic solids , 1992 .

[15]  Huajian Gao,et al.  Cavitation in materials with distributed weak zones: Implications on the origin of brittle fracture in metallic glasses , 2013 .

[16]  Yanfei Gao,et al.  Thin-film metallic glasses for substrate fatigue-property improvements , 2014 .

[17]  Jiaxi Zhao,et al.  Plastic deformability of metallic glass by artificial macroscopic notches , 2010 .

[18]  U. Ramamurty,et al.  Mixed mode (I and II) crack tip fields in bulk metallic glasses , 2009 .

[19]  V. Tvergaard.  Material Failure by Void Growth to Coalescence , 1989 .

[20]  J. Schroers,et al.  Designing tensile ductility in metallic glasses , 2013, Nature Communications.

[21]  Mariana Calin,et al.  Metallic glasses: Notch-insensitive materials , 2012 .

[22]  L. Dai,et al.  Failure criterion for metallic glasses , 2011 .

[23]  Z. Suo,et al.  Notch-sensitivity and shear bands in brittle matrix composites , 1994 .

[24]  Z. S. Liu,et al.  Necking and notch strengthening in metallic glass with symmetric sharp-and-deep notches , 2015, Scientific Reports.

[25]  Yanfei Gao,et al.  On the shear-band direction in metallic glasses , 2011 .

[26]  Huajian Gao,et al.  Origin of anomalous inverse notch effect in bulk metallic glasses , 2015 .

[27]  Huajian Gao,et al.  On the notch sensitivity of CuZr metallic glasses , 2013 .

[28]  Jiaxi Zhao,et al.  Comparison of compressive deformation and fracture behaviors of Zr- and Ti-based metallic glasses with notches , 2011 .

[29]  Huajian Gao,et al.  Shear bands mediate cavitation in brittle metallic glasses , 2013 .

[30]  Reinhold H. Dauskardt,et al.  Local heating associated with crack tip plasticity in Zr–Ti–Ni–Cu–Be bulk amorphous metals , 1999 .

[31]  Mehdi Jafary-Zadeh,et al.  Mechanisms of failure in nanoscale metallic glass. , 2014, Nano letters.

[32]  Yanfei Gao,et al.  Intergranular strain evolution near fatigue crack tips in polycrystalline metals , 2011 .

[33]  Yong-Wei Zhang,et al.  Cavitation in brittle metallic glasses – Effects of stress state and distributed weak zones , 2014 .

[34]  P. Liaw,et al.  Interface Constraints on Shear Band Patterns in Bonded Metallic Glass Films Under Microindentation , 2012, Metallurgical and Materials Transactions A.

[35]  U. Ramamurty,et al.  On the mechanism and the length scales involved in the ductile fracture of a bulk metallic glass , 2013 .