Formation of Ti-Zr-Ni-Cu-Be-Nb bulk metallic glasses

The investigations of the phase constitutes and microstructure were performed on as-cast (Ti₄₀Zr₂₅Ni₈Cu₉Be₁₈)_100-xNb_x (x = 0, 3, 5, 8, 10) (Ø 3) glass forming alloys. Large quantities of icosahedral quasicrystals are found to distribute in the glassy matrix of alloys with Nb content 3 and 5 at.%, fully amorphous phase with 8 at.% Nb, and a few nanocrystals corresponding to a CuTi-phase precipitating in the glassy matrix with 10 at.% Nb. In addition, 8 at.% Nb-containing alloy exhibits relatively good glass forming ability as well as Nb-free alloy. The activation energy for the first crystallization of this alloy is 249.80 kJ/mol, larger than that of the Nb-free alloy; moreover, this alloy possesses higher room temperature compressive fracture strength (2083 MPa), although it exhibits smaller plasticity (2.1%) than that of Nb-free alloy.