Effects of Sn addition on mechanical properties of Ti-based bulk metallic glass composites

Ti-based bulk metallic glass (BMG) composites were prepared by a minor addition of Sn to match the Young's modulus of dendrite-phase and glass-matrix, and prepared by suction casting into a water-cooled copper mold. The largest compressive fracture strain of 28.07% and the highest fracture strength of 1820 MPa are obtained simultaneously in the Ti₄₅Zr₂₅Nb₆Cu₅Be₁₇Sn₂ BMG composite. The average stress concentration factor of dendrite-phase, which characterizes the concentrated stress in the dendrite-phase that is transferred to the glass-matrix through the interface, is found to be highly related to the mechanical properties and thus would be a guide for matching the Young's modulus. The microscopic deformation mechanism shows that the high average stress concentration factor of dendrite-phase promotes the transfer of concentrated stress from the dendrite-phase to the glass-matrix, thus leading to the formation of multiple shear bands. Matching the Young's modulus of dendrite-phase and glass-matrix is concluded to be a useful recipe to prepare the BMG composites with excellent mechanical properties.