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摘要
The micro-actuater materials are needed urgently in micro-electro-mechanical systems (MEMS) which are developing rapidly. The melt-spun Ti-Ni shape memory alloy ribbons have become candidate materials since their fast heat response and large acting density. The bulk Ti-47Ni (atom fraction, %) shape memory alloy is an ideal material to make thermosensitive actuators since its one-stage martensitic transformation and small temperature hysteresis. In order to develop the micro-actuator materials with fast response using in MEMS, the chilled Ti-47Ni alloy ribbons were fabricated by melt-spinning in this research. The effects of the roller speed and the annealing processes on microstructure, phase composition, phase transformation behaviors and shape memory effect of Ti-47Ni alloy ribbons were investigated by CLSM, XRD, DSC and bending test. The results show that the microstructure of as-cast and 300 similar to 800. annealed Ti-47Ni alloy ribbons fabricated under different roller speeds is vertically and horizontally arrayed columnar. The higher the roller speed, the finer the grain is. The annealing processes do nearly affect the microstructure of the alloy ribbons. The composition phases of Ti- 47Ni alloy ribbons are martensite (B19' phase, monoclinic structure) and parent phase (B2 phase, CsCl- type structure). The B2 -> B19'/B19'-> B2 type one-stage martensitic transformation occurs in Ti- 47Ni alloy ribbons upon cooling and heating, the martensitic transformation temperature and the reverse martensitic transformation temperature are about 54 and 81 degrees C respectively, and the temperature hysteresis is about 27 degrees C With increasing the roller speed, the martensitic transformation temperatures of the alloy ribbons decrease, and the recovery rate of shape memory of the alloy ribbons increases. With increasing the annealing temperature, the transformation behaviors of the alloy ribbons change a little, and the recovery rate of shape memory changes in the range of 93%similar to 98%. The as-cast and annealed Ti-47Ni alloy ribbons are all of excellent shape memory effect.
- 出版日期2018-8-11
- 单位陕西理工大学
