Abstract: The Mo₅Si₃ base alloys with a series of transition metal elements were prepared by arc-melting, and were annealed at 1250℃ in vacuum for 24h. Ternary alloying effect was investigated by X-ray diffractometry (XRD), optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy(EDS). The EDS results show that Zr, Ti, Co and V have certain solubility in homogenized Mo₅Si₃, which are determined to be 2.20±1.42,15.94±0.18,3.33±0.76 and 7.43±0.22 (mole fraction, %), respectively. Microstructural characteristics indicate that all studied alloys have a two-phase microstructure, i.e., Mo₅Si₃ matrix and the second phase Mo₃₇Zr₂₀Si₄₃,Mo₆₆Si₁₉Ti₁₅ ,MoCoSi or (Mo, V)₃Si.

Key words:  silicides; alloying effect; microstructure