Thermomechanical analysis of nitinol memory alloy behavior

Shape memory alloys are functional materials characterized by the effect of shape and superelasticity. Due to these properties, they widely used, particularly, in bioengineering, aeronautics, robotics civil engineering. The temperatures phase transformations influence external temperature strain rate on mechanical characteristics Ni55.75Ti44.15 alloy investigated this paper. is obtained differential scanning calorimetry (DSC) range from -70°C 70°C. Diagrams calorimeters at different heating cooling rates constructed analyzed. Samples for tests made round rod 8 mm diameter. samples working area 12.5 length 4 Mechanical carried out close maximum value completion martensitic-austenitic transformation Af = 14.7°C. deformation under uniaxial tension stresses transformations, Young's modulus relative elongations areas loading speeds exterior determined. Using Clausius-Clapeyron formula, it shown that with simultaneous changes rate, largely due rather than load rates. coefficients equation superelastic memory, which consistent those known literature,