A universal criterion for plastic yielding of metallic glasses with a (T/Tg)2/3 temperature dependence -: art. no. 195501

Room temperature (T-R) elastic constants and compressive yield strengths of similar to 30 metallic glasses reveal an average shear limit gamma(C)=0.0267 +/- 0.0020, where tau(Y)=gamma(C)G is the maximum resolved shear stress at yielding, and G the shear modulus. The gamma(C) values for individual glasses are correlated with t=T-R/T-g, and gamma(C) for a single glass follows the same correlation (vs t=T/T-g). A cooperative shear model, inspired by Frenkel's analysis of the shear strength of solids, is proposed. Using a scaling analysis leads to a universal law tau(CT)/G=gamma(C0)-gamma(C1)(t)(2/3) for the flow stress at finite T where gamma(C0)=(0.036 +/- 0.002) and gamma(C1)=(0.016 +/- 0.002).