Shape Memory Alloy actuating materials for MEMS/Robotics

In 2005, funds allocated to this project have been used to support;

1. The synthesis of Ni-Ti films (as outlined below)
2. The research work of a mastter of engineering practice thesis entitled "Design, Fabrication, and Performance Evaluation of a TiNi SMA Based Microgripper"
3. The purchase of a single axis laser displacement sensor and a user-friendly data acquisition system to set up an experimental research environment

Ni-Ti thin films, with a composition of Ni-50at%Ti have been prepared using filtered arc deposition. The type of substrate was found to have a significant effect on the film: Si substrates produced fully crystalline films, glass substrates had a duplex structure of small (~20nm) parent phase grains within an amorphous matrix. Both films were predominantly parent phase, whereas a bulk alloy of the same composition would be martensite. This stabilisation of the parent phase is proposed to be the result of the unusually small grain size in the films, and the critical grain size for parent phase stabilisation has been determined to be 30nm. Thsi is believed to be the first observation og frain size stabilisation in this alloy system. An ARC Discovery Project application has been submitted in the current round to further explore this fascinating area.