Papers by Author: Rui Miguel S. Martins

Abstract: A sputter deposition chamber inserted into the six-circle Huber diffractometer of the materials research station of the ROssendorf BeamLine (ROBL-CRG) at ESRF allowed to perform in-situ experiments during film growth of Ni-Ti. It is equipped with Kapton windows for X-Ray Diffraction (XRD) and specular Reflectivity (XRR) measurements. By following in situ the evolution of the structure of the growing film, we reveal intermediate “states” which cannot be seen/revealed ex situ, because those states occurred only during the growth but were no longer visible after deposition. Vertical Bragg-Brentano large-angle scattering geometry was employed to study the different trends of structural transformations taking place during deposition. Ni-Ti films exhibiting a non-uniform phase content across the film thickness could be produced by varying the power of co-sputtering Ni-Ti plus Ti. A significant decrease of IB2{110}/IB2{200} was observed when a bias of -45 V was applied.

Abstract: The aim of the present experiment was to analyse the structural evolution during annealing of Nickel-Titanium (Ni-Ti) SMA subjected to different thermomechanical treatments. As structural evolutions are accompanied by the changes in preferential orientations, pole figures were employed to study the in-situ conditions.