Fracture in metallic glasses: mechanics and mechanisms

Toughness of Bulk Metallic Glasses

“…The corresponding fracture surface then shows the vein patterns typified by Figure 1a. These patterns resemble those found on separating two glass plates with a viscous medium in between and this mechanism fracture is called the fluid meniscus instability (FMI) mechanism [13,37,38]. A key parameter here is also the curvature radius of the crack tip, R. As shown by Jiang et al [39], the FMI mechanism can operate only if the curvature radius, R is higher than λc.…”

“…Under the action of a stress gradient, perturbations with a critical wavelength will grow into the material ahead of the crack tip, in the process creating a new crack tip with a viscous zone ahead of it. The process repeats, leading to the formation of nanoscale corrugations (NCs) [38,40]. Others, however, hold different views and it has been asserted that FMI is unlikely to play a role in NC formation [38,41].…”

“…The process repeats, leading to the formation of nanoscale corrugations (NCs) [38,40]. Others, however, hold different views and it has been asserted that FMI is unlikely to play a role in NC formation [38,41]. Narasimhan et al [38], for example, have argued that the FMI mechanism predicts the formation of fingers that should run perpendicular to the crack front, whereas the NCs (as in Figure 1d) run parallel to the crack front.…”

“…Others, however, hold different views and it has been asserted that FMI is unlikely to play a role in NC formation [38,41]. Narasimhan et al [38], for example, have argued that the FMI mechanism predicts the formation of fingers that should run perpendicular to the crack front, whereas the NCs (as in Figure 1d) run parallel to the crack front. Molecular dynamics simulations by Murali et al [42] on a ductile glass (CuZr) and a brittle glass (FeP) have shed considerable light on the possible mechanisms.…”

Improvement of dynamic notch toughness for the Zr 56 Co 28 Al 16 bulk metallic glass by local pre-deformation

“…However, the limited ductility of BMGs is taken as an obstacle to prevent their widespread usage [6,7]. Therefore, designing BMG components on the basis of strength is not appropriate since it may lead to low reliability [8].…”