Effects of Nb on the formation of icosahedral quasicrystalline phase in Ti-rich Ti–Zr–Ni–Cu–Be glassy forming alloys

As-cast (Ti40Zr25Ni8Cu9Be18)100−xNbx (0 ⩽ x ⩽ 5) (Ф3) glassy forming alloys were investigated in order to clarify the role of Nb on the formation of icosahedral quasicrystalline phase (I-phase) in Ti-rich Ti–Zr–Ni–Cu–Be glassy system. It is found that an I-phase is formed in Ti–Zr–Ni–Cu–Be glassy alloy by addition of Nb element; however, the nucleation rate of I-phase increases, whereas the grain growth rate decreases with increasing Nb content. Moreover, with increasing Nb content, the thermal stability against crystallization increases, while the temperature range of stability of the I-phase decreases.