Abstract
An in situ formed (Cu0.6Zr0.25Ti0.15)93Nb7 bulk metallic glass (BMG) composite was prepared successfully. The ductile Nb-rich crystalline phase with a dendritic structure disperses homogeneously in the BMG matrix. The mean size of the dendritic Nb phase is about 5∼10 μm. For Cu-Zr-Ti-Nb glassy ribbons, the additions of Nb element cause the glass transition and crystallization onset temperature to shift to much higher values, and improve the thermal stability of the glassy phase. For the in situ formed (Cu0.6Zr0.25Ti0.15)93Nb7 bulk metallic glass composites, its glass transition temperature and crystallization onset temperature is almost the same as those of the Nb-free Cu60Zr25Ti15 BMG, implying that almost all the added Nb element precipitates from the melt upon cooling. The (Cu0.6Zr0.25Ti0.15)93Nb7 BMG composite also presents a good combination of excellent mechanical properties. The compressive fracture strength and fracture elongation are 2130 MPa and 6.4%, respectively. The increase in elongation results from the homogeneous dispersion of the ductile and dendritic Nb-rich crystalline phase in the BMG matrix.
