Deformation Behavior of Nb-Si-Fe-Ti-Al-W In Situ Composite At Elevated Temperature

A Nb-16Si-5Fe-10Ti-5Al-10W multiphase composite was prepared by mechanical alloying (MA) and hot pressing sintering. Influence of milling time on relative density was studied. The results show the relative density increases with increasing milling time. Analysis of XRD reveals that this composite consists of Nbss(Niobium solid solution), intermetallics Nb₅Si₃ and Nb₄Fe₃Si₅. The average grain sizes of each phase are all about 1 μm and the grains shapes are nearly equiaxed. The tensile properties of Nb-16Si-5Fe-10Ti-5Al-10W composite at elevated temperature were evaluated by tensile tests in vacuum. This composite displayed extensive plasticity or superplasticity at or above 1 350 ℃ with strain rate of 3.1×10^-4 s^-1. The main plastic deformation mechanism is grain boundary sliding. This composite exhibited very high tensile strength at 1 300 ℃ and 1 350 ℃.