Computational Study of Density Fluctuation-Induced Shear Bands Formation in Bulk Metallic Glasses

Seemingly identical Bulk Metallic Glasses (BMG) often exhibit strikingly different mechanical properties despite having the same composition and fictive temperature. A postulated mechanism underlying these differences is the presence of "defects". Here we investigate this hypothesis through the study of the effect of density fluctuations on shear band formation under an applied stress. We find that the critical shear stress is strongly dependent on the magnitude and size of the fluctuations. This finding also elucidates why, historically, critical shear stresses obtained in simulations have differed so much from those found experimentally, as typical simulations setups might favor unrealistically uniform geometries.