Non-equilibrium Phases in Cu-Al and Cu-Al-Ni Shape Memory Alloy Thin Films grown by DC Magnetron Sputtering.

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

Merida

Congreso; 11th Inter-American Congress on Microscopy, 25-29 Sept. 2011, Mérida, México.; 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, themartesite transforms to the austenite and recovers the original shape. Thin films of Ni-Ti alloys havebeen extensively studied in the literature. Alternatively, Cu-based alloys present the advantage thatare cheaper, have lower hysterisis and higher range of operating temperatures. However, there arestill several aspects to be improved in their fabrication.