Effect of annealing process on the changes in crystalline structure of TiNiCu amorphous ribbon

摘要

Shape memory alloys (SMA's) have become one of the major elements of intelligent structures and mechanisms (e.g. sensors, actuators, and active biomaterials) due to their unique thermo-mechanical properties. The main features of SMA's are related to a reversible martensitic transformation that can be induced either thermally or by applying stress. In this study, crystalline structure and changes in phase composition of TiNiCu samples were investigated mainly using an X-ray diffraction (XRD) method. Amorphous ribbons with the composition Ti_(50)Ni_(25)Cu_(25) were characterized under various temperatures during annealing. Changes in crystalline structure have been shown to be dependent on the executed processes. XRD measurement results revealed that heat treatment annealing yields totally the crystalline structure of amorphous structure and martensite is the major phase.