Investigation of pressure effect on microstructure and physical properties of NiTi alloy

In this study, diameter 3.5 mm wire form (Ni %44,74 Ti at.) shape memory alloys was cut into small pieces. After all brought to the same standards the cut samples was applied in different ratios pressure one unpressurized other 5 samples. Differential scanning calorimetry (DSC) with the alloy was determined martensite and austenite phase transformation temperature. The phase transformation temperatures of the alloy have changed with the applied pressure. Determination of the surface morphology of the samples received and the image areas to determine the amounts of the elements was carried out with scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. The effect of pressure on the grain boundaries was observed. Increasing the pressure applied on the sample was observed to increase grain boundary formed on the surface. To investigate the changes were measured in the stiffness of the sample stiffness. The measurements carried out by increasing the pressure applied to the samples after a certain pressure value has increased observed hardness drops. Key Words: NiTi shape memory alloy, activation energy, Entalpy, Pressure