Formation of Ductile Cu-Based Bulk Metallic Glass Matrix Composite by Ta Addition

The Effect of the Ta addition on the fabrication of the ductile phase reinforced Cu-Zr-Ti bulk metallic glass (BMG) matrix composite was investigated. A composite microstructure consisted of μm-scale Ta-rich solid solution particles distributed in the BMG matrix was successfully obtained by injection casting of the (Cu₆₀Zr₃₀Ti₁₀)₉₅ Ta₅ alloy into a copper mold. Ta-rich solid solution particles were observed to form first in the liquid melt during solidification, while the remaining melt solidified into the amorphous phase at lower temperature. The monolithic Cu₆₀Zr₃₀Ti₁₀ BMG shows a compressive strength of 2080 MPa and a fracture strain of 3.3%, while the (Cu₆₀Zr₃₀Ti₁₀)₉₅Ta₅ BMG matrix composite shows compressive strength of 2320 MPa and, in particular, a significantly improved plastic strain to failure of about 14.5%. The remarkable ductility improvement in the (Cu₆₀Zr₃₀Ti ₁₀)₉₅Ta₅ composite could be explained by the presence of the highly ductile Ta-rich particles.