Ni-Ti samples were prepared by powder metallurgy. The prepared samples were master samples M 1 (55% Ni-45%Ti) and M 2 (56% Ni-44%Ti). The additive percentage of Ta was 5%, 7% and 9% to master sample M 1 and M 2 , while Nb addition was 1%, 2% and 4% to M 1 and M 2 . The pressure of pressing was 800 Mpa. The samples were sintered at 950 °C for a time of 9 hr. Samples were then examined by using SEM technique, XRD, DSC, Vickers hardness. The porosity was measured according to Archimedes method.

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... nning electronic microscopy images showed that most prepared samples have porosity, which in turn imparts decreasing microhardness values across the surface. Better increase of microhardness values is found in M 2 +5%Ta. Scanning electron microscopy indicated also the best martensitic structure in M 1 +4% Nb and M 2 +4%Nb. X -ray diffraction observations indicated that NiTi, Ni 3 Ti and NiTi 2 phases exist in all samples. NiTi phase is playing a dramatic role in enhancing shape memory effect and superelasticity. DSC results show that transformation temperatures range in (46-134°C). This indicates that all samples at room temperature have one phase which is martensite.