The effect of heat treatment on the mechanical strength of a three-phase NbSS/Nb5Si3/Cr2Nb alloy with composition Nb–22Ti–12Si–14Cr–2Al–2Hf was investigated. This included the evaluation of microstructure, room temperature mechanical strength and the fracture behaviours. The microstructures of heat treated samples were composed of NbSS, Nb5Si3 and Cr2Nb, and the phase size changed under different heat treatment schemes. The results showed that the microstructure composed of large NbSS and fine Nb5Si3 exhibited best mechanical strength due to the deformation of NbSS in these samples. Moreover, fractographic analysis indicated that the Nb5Si3 and Cr2Nb fractured in cleavage manner in all heat treated samples.
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