Shape memory effect in thin films of a Cu-Al-Ni alloy

F.C. LOVEY; A.M. CONDÓ; J. GUIMPEL; M.J. YACAMÁN

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

ELSEVIER SCIENCE SA

Año: 2008 vol. 481 p. 426 - 430

0921-5093

Thin films of Cu-26.9 at.% Al-5.5 at.% Ni were grown by dc magnetron sputtering from the alloy target previously melted in an induction furnace. The films were grown either on glass or   (1 0 0)Si substrates at room temperature. The films, of approximately 3 mm thickness, were peeled off from the substrate for further studies. The structures and microstructures of the as grown films were analysed by transmission electron microscopy. A nanometric mixture of BCC and 2H phases was found irrespective of the substrate. The shape memory effect was not observed for this structural state. After an annealing at 1023K for 3600 s in He or Ar flux, followed by quenching to room temperature, the films were found to be in a martensitic state. Mainly the 18R structure was observed. At this stage the films were mechanically deformed at room temperature and then heated up to 373 K. A good shape recovery was observed to take place in a temperature range between 334 and 360 K.