A strategy for designing bulk metallic glass composites with excellent work-hardening and large tensile ductility

Abstract

Bulk metallic glass (BMG) composites have demonstrated enormous potential for improved ductility and toughness over the traditional BMGs by in-situ formed crystalline phase in glass-matrix, which brings about delocalized strain and can inhibit shear bands rapid propagation in glass-matrix. However, an early onset of necking after yielding arises upon tension loading process. Enhancing work-hardening of bulk metallic glass (BMG) composites is therefore vitally important for practical applications. By tailoring the intrinsic properties of a Ti47Zr25Nb6Cu5Be17 BMG composite with an addition of Sn to reduce the shear and the elastic modulus of dendrite-phase, the current work gives full play to strain-induced work-hardening of dendrite phase and makes it succeed the completion with strain-induced work-softening of glass-matrix. Because of the significant enhancement of work-hardening by dislocation deformation in dendrite-phase, and the stabilized plastic flow in glass-matrix, large tensile ductility (tensile strain till necking εu ≈ 10%) and high tensile strength (σu ≈ 1.5 GPa) are attained simultaneously by the Sn2 BMG composite.