SHAPE MEMORY INVESTIGATION OF SMART CAMAR LOGO USING NITI ALLOY WIRE

This project is investigates of NiTi shape memory alloy for simple smart application. The shape memory effect (SME) is attributed from the reversible phase transformation when subjected to stress and temperature. In this study, a small model of CAMAR logo was designed to mimic the shape memory effect. Three samples of wire were investigated; (i) Austenitic NiTi (ii) Martensitic NiTi and (iii) commercial plain carbon steel. The reversible austenite to martensite transformation of the NiTi wire was investigated by a differential scanning calorimetry (DSC) at temperatures ranging from -50 and 200 degrees C. The wire was shaped into CAMAR logo using a mould and then heated at 500 degrees C for 30 minutes in a high temperature furnace. To observe the shape effect recovery, the wire was straighten and reheated in warm water at different temperatures. Results showed that the austenitic wire exhibited complete shape memory recovery after heated at temperature approximately 35 degrees C and 80 degrees C. For the martensitic wire, complete recovery was only observed when the water temperature was similar to 80 degrees C and no recovery was observed at similar to 30 degrees C. This recovery effect was significantly influenced by the reversible phase transformation temperatures (PTTs) which attributed from the Austenite finish (A(f)) temperature.