Microstructure evolution and mechanical properties of Nb-alloyed Cu–Zr–Al–Ni large-sized metallic glass composites

The effects of Nb on the microstructures and mechanical properties of large-sized (Cu0.47Zr0.47Al0.06)99 − xNi1Nbx (x = 0, 0.5, 1, 2 at.-%) bulk metallic glass composites were investigated. It is verified that the liquidus temperature (Tl) of the Nb-added alloys decreases to cause the increase of glass-forming ability (GFA). The addition of Nb adjusts the distribution and the volume fraction of B2-CuZr phase in the Cu–Zr–Al–Ni large-sized composites by changing the GFA of the alloys. The mechanical properties of the composites strongly depend on the volume fraction and distribution of B2-CuZr phase in the glassy matrix. The alloy with 0.5 at.-% Nb addition exhibits the high mechanical properties, which should be attributed to the uniform distribution and the proper volume fraction of B2-CuZr phase in the glassy matrix.