"Effects of Milling and Annealing On Preparation and Structural Evaluation of Nanostructured Niticu Shape Memory Alloy"

The technique of mechanical alloying is used to obtain NiTiCu shape memory alloy with nanocrystalline structure.  A stoichiometric mixture of high purity elemental powders of Ni, Ti and Cu with a nominal composition NiTiCu5 was subjected to intense mechanical treatment in a high energy ball mill in different milling condition. Fabricated alloys were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD results demonstrated that after 60 h milling, the Cu dissolved into B2 structure and NiTi phase was obtained. Annealing of produced alloys at 1173 K for 900 s led to formation of nanometric NiTiCu phase, release of internal strain and grain growth. The SEM and TEM analysis showed that this method resulted in formation alloys with appropriate morphology and homogeneous structure.