| Title |
Research Paper - Transformations - : Effects on Annealing Process on the Structure and Ms Temperature of NiAlFe Shape Memory Alloys |
| Authors |
이동현(Dong Hyun Lee); 최창수(Chang Soo Choi); 정인상(In Sang Chung) |
| Abstract |
An attempt to improve ductility of the NiAl-base shape memory alloys has been made by the addition of Fe. Also, the effect of the annealing treatment on the microstructure and the transformation temperature of the NiAl-base shape memory alloy has been studied. It has been found that a small amount of γ phase (fcc) formed by the addition of Fe has a drastic effect on the hot workability. The transformation temperature increases with increasing the annealing temperature and the annealing time causing the variation of the composition and the volume fraction of matrix, which is composed of β phase. The variation of shape recovery with increasing of the annealing temperature is due to the change of the volume fraction of martensite caused by the variation of composition, the fraction of β phase, the morphology of γ phase and the grain growth of β phase. The transformation temperature and the shape memory effect are controlled by annealing at the appropriate temperature in the coexisting region of β and γ phase. |