ELECTRON DIFFRACTION STUDY OF STRUCTURES IN Cu-Al-Ni SHAPE MEMORY THIN FILMS GROWN BY SPUTTERING

C. ESPINOZA TORRES; A.M. CONDÓ; F.C. LOVEY; E. ZELAYA; J. GUIMPEL

Congreso; 17th International Microscopy Congress; 2010

The shape memory effect (SME) is present in Cu-Al-Ni alloys in a certain range of compositions. In this paper we characterize the microstructure of thin films of Cu-Al-Ni grown by sputtering on Si (100) at room temperature from a target alloy of Cu-27.35 at.% Al-5.45 at.% Ni. The 5 um thick films were analyzed by transmission electron microscopy (TEM) in a Philips CM200 UT microscope. Cross sections specimens were prepared by Focused Ion Beam (FIB). From the electron diffraction patterns calibrated by X-Ray Diffraction (XRD) the lattice parameters of the 2H hexagonal structure described by an orthorhombic cell were obtained: a=0.453 nm, b=0.523 nm and c=0.424 nm and for the BCC structure a = 0.292 nm. Three main variants are present in the Cu-Al-Ni thin film. They were identified as [001]2H, [100]2H and [110]BCC, being the first one the most observed.