The influence of heat treatments on the phase composite and mechanical properties of Ni 47 Ti 44 Nb 9 alloy were investigated by using XRD, SEM, TEM and EDX. The results show that a diffusional transformation takes place when the alloy is heated over 850 ℃ for a long time, and a new precipitation (Ni,Nb) 3Ti with an hcp structure can be found. The formation of the precipitation leads to an increment of microhardness and reduction in elongation.
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