Relation between ideal and real strengths of metallic glasses

Available experimental data of about 110 metallic glasses show that the ratios of room-temperature strengths to low-temperature ideal strengths have universal upper and lower bounds. The two bounds are rationalized by taking cooperative shearing of shear transformation zone (STZ) operations into consideration in the potential energy landscape thermodynamics. It is striking to find that the real-to-ideal strength gap results from both configurational and thermo-vibrational contributions to STZs. The former determines the upper bound, while the latter further decreases strengths to the lower bound. The results may shed new insight into metallic glass strength and flow.