PREDIC'rABLE BEHAVIOR OF SMART MATF~RIAI~ (Cu-Zn-A! 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 to N 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 mieromemory effects. Also, the room temperature effects on the parent phase (for instance, summer to winter) acting over the transformation temperature are quantified.