Macroscopic tensile plasticity of bulk metallic glass through designed artificial defects

Catastrophic fracture with nearly zero tensile elongation at room temperature in bulk metallic glasses (BMGs) makes their future application as structural materials seem bleak. The instable localized shear banding with “work softening” under unconfined uniaxial tension should be responsible for the zero elongation. Here we show how to control the shear band and make it contribute to the macroscopic tensile plasticity of BMGs through designed artificial defects. By promoting the initiation of shear bands and hindering their instable propagation through introducing artificial defects, appreciable macroscopic tensile plasticity was successfully achieved in a conventional Zr-based BMG. Moreover, by designing the distribution of the defects to inhibit the intrinsic shear fracture, the nominal tensile strength and elongation of the BMG have been enhanced simultaneously. The principles for toughening BMG through designed artificial defects are proposed; accordingly, some strategies for designing future porous BMG materials with high mechanical performance were presented.

► A strategy to improve the tensile plasticity of conventional BMGs is proposed and proved experimentally.
► A simultaneous enhancement of strength and plasticity is found in the BMG materials.
► Principles include not only the introduction but also the design of artificial defects.
► One example to apply the present strategy for developing future porous BMG is presented.