Nb-silicide based alloys have high melting point(above 1900℃), low density(6.6~7.2g/cm3), high specific stiffness, good high temperature strength and excellent high temperature creep resistance, which make it one of high temperature structural materials with potential aero-engine applications. However, the room temperature toughness of the alloy is low, and its high temperature strength is not enough. Therefore, it has importantly theoretical and practical significance to prepare alloys with excellent mechanical properties at room and elevated temperature.
In this paper, Nb-silicide alloy with composition of Nb-22Ti-16Si-3Cr-3Al-2Hf（at.%）
was directionally solidified into square ingots at different processing parameters through a novel cold crucible directional solidification technology. The effect of directionally solidified processing parameters, such as heating power and withdrawal rate, on the microstructure and mechanical properties was analyzed. Results show that the directional structure composed of coupled growth of (Nb,Ti)ss/(Nb,Ti)5Si3 composite can exhibit good tension performance at 1250℃.