Non-equilibrium Phases in Cu-Al and Cu-Al-Ni Shape Memory Alloy Thin Films

C. ESPINOZA TORRES; N. HABERKORN; A. M. CONDÓ; F. C. LOVEY; J. GUIMPEL

Congreso; 11th Inter-American Congress on Microscopy; 2011

Shape memory alloy (SMA) thin films have the potential to become primary actuating mechanismfor mechanical devices with dimensions in the micron range requiring large forces over longdisplacements. The shape memory effect involves a thermally induced crystalline transformationbetween the martensite and austenite which are the low and high temperatures phases respectively. On a microscopic level, deformation of the martensite occurs by preferential alignment of twins, which is a reversible process, unlike deformations associated with dislocations. When heated, the martesite transforms to the austenite and recovers the original shape. Thin films of Ni-Ti alloys have been extensively studied in the literature. Alternatively, Cu-based alloys present the advantage that are cheaper, have lower hysterisis and higher range of operating temperatures. However, there are still several aspects to be improved in their fabrication.In this work we analysed the microstructure of Cu-Al and Cu-Al-Ni thin films grown by DC magnetron sputtering.