The Study of Phase Transformation and Thermoelasticity Behavior of Nanocrystalline NiTiCu Compound Synthesized by Mechanical Alloying Process

NiTiCu intermetallic compound with nanocrystalline structure was successfully synthesized through mechanical alloying and subsequent annealing process. The X-ray diffraction (XRD) analysis revealed that after 60 h milling of high purity elemental powders mixture of Ni، Ti and Cu via a planetary high energy ball milling، the Cu dissolved into B2 structure and NiTiCu phase was obtained. Annealing of as-milled powders at 1173 K for 15 min leads to formation of nanometric NiTiCu (B19'') phase، grain growth and release of internal strain. Structural characterization was examined by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The results demonstrated that this route result in preparation compounds with suitable morphology and homogeneous structure. Formation of nanometric structure enhances thermoelasticity and shape memory behavior in this compound by narrowing the thermal hysteresis.