Experimentelle und theoretische untersuchungen des last - Verformung-Verhaltens von CuZnAl und CuAlNi-einkristallen

When a stress is applied to a shape memory alloy in the martensitic state, the deformation proceeds by the movement of intervariant boundary, while the deformation at higher temperature is caused by the stress-induced martensitic transformation. The load deformation behavior is investigated at different temperatures. Comparing the results with the Landau-Devonshire model we find that the pseudoelastic hysteresis loops are not in agreement with this model. The thermodynamic analysis shows that the size of the hysteresis loops is determined by a coherence energy which is measured in CuZnAl and CuAlNi single crystals. This energy is a material constant and independent of temperature.