Predictable behavior of smart materials (Cu-Zn-Al SMA)

Reliability is a critical word in industrial applications of Shape Memory Alloys. Accurate and reproducible transformation hysteresis cycles and internal loops were obtained in single crystals using a high resolution automatized equipment. From a mechanical model formulated for a single martensite plate, the shape of the hysteresis cycle is obtained by generalizing the representation toN plates. The observed time effects on the hysteresis loops related to diffusion processes were also taken into account. It allows to explain the martensite recoverable creep and the micromemory effects. Also, the room temperature effects on the parent phase (for instance, summer to winter) acting over the transformation temperature are quantified.Research carried out under the project NATO 920452. Partial support from CICYT is gratefully acknowledged. V. T. acknowledges Dir. Pol. Terr. (Generalitat of Catalonia) for useful support. Fruitful discussions with Drs. F. C. Lovey and J. L. Pelegrina of CAB-Argentina (EEC-ALA/MED contract) are acknowledged.