SIZE EFFECT IN THE DEFORMATION AND FAILURE OF METALLIC GLASS
Recent experimental and theoretical work have suggested possible size effect in the plasticity and failure resistance of metallic glasses.While bulk metallic glasses manifest negligible tensile ductility,nanoscale metallic glasses show significant ductility under tension (PNAS 104,11155).Nanopillar compression experiments also show intriguing behavioral differences sensitive to pillar size.Multiple reasons could contribute to this size dependence: (a) proliferation of amorphous-crystal interfaces or surfaces that directly mediate plasticity,as well as indirectly alter the glass structure,(b) Weibull-like statistics for the nucleation of a runaway flow defect from the condensation of shear transtbrmation zones in a finite volume,and (c) intrinsic thermomechanical lengthscales,such as the glue zone width in the aged-rejuvenation-glue-liquid model of a runaway shear band (Acta Mater.54,4293).A Hall-Petch like relationship may exist with respect to the metallic glass sizescale,but for the useful ductility (tensile and compressive) instead of strength.
Ju Li
Department of Materials Science and Engineering,University of Pennsylvania,Philadelphia,PA 19104-6272,USA
国际会议
第二届国际非均质材料力学会议(The Second International Conference on Heterogeneous Material Mechanics)
安徽黄山
英文
364
2008-06-03（万方平台首次上网日期，不代表论文的发表时间）