Remarks on the Notch Sensitivity of Bulk Metallic Glasses

Since the degree of stress triaxiality can be easily manipulated in notched samples, tests on them can provide crucial information to verify various constitutive models of bulk metallic glasses (BMGs). Oftentimes, notched samples exhibit enhanced ductility, but their strength can be reduced or improved, or even be insensitive to, the notch geometric parameters. Based on a comparison of notch studies on conventional metallic materials (that exhibit cavitation-controlled failure) and composites (that exhibit crack bridging), as well as by assembling many recent notch studies on BMGs, this review assesses the following key factors: the role of stress triaxiality in the atomistic processes for free volume evolution, the competition between and synergy of shear banding and cavitation failure, and the geometric arrangements of shear bands that delay shear or cavitation failure. Difficulties that prevent unified predictions are also explained.