Epitaxial versus polycrystalline shape memory Cu-Al-Ni thin films
Bilican, Doğa (Universitat Autònoma de Barcelona. Departament de Física)
Kurdi, Samer (University of Cambridge. Department of Materials Science and Metallurgy)
Zhu, Yi (University of Cambridge. Department of Materials Science and Metallurgy)
Solsona Mateos, Pau (Universitat Autònoma de Barcelona. Departament de Física)
Pellicer Vilà, Eva Maria (Universitat Autònoma de Barcelona. Departament de Física)
Barber, Zoe H. (University of Cambridge. Department of Materials Science and Metallurgy)
Greer, Alan Lindsay (University of Cambridge. Department of Materials Science and Metallurgy)
Sort Viñas, Jordi (Universitat Autònoma de Barcelona. Departament de Física)
Fornell Beringues, Jordina (Universitat Autònoma de Barcelona. Departament de Física)

Date:	2019
Abstract:	In this work, two different approaches were followed to obtain Cu-Al-Ni thin films with shape memory potential. On the one hand, Cu-Ni/Al multilayers were grown by magnetron sputtering at room temperature. To promote diffusion and martensitic/austenitic phase transformation, the multilayers were subjected to subsequent heat treatment at 800 °C and quenched in iced water. On the other hand, Cu, Al, and Ni were co-sputtered onto heated MgO (001) substrates held at 700 °C. Energy-dispersive X-ray spectroscopy, X-ray diffraction, and transmission electron microscopy analyses were carried out to study the resulting microstructures. In the former method, with the aim of tuning the thin film's composition, and, consequently, the martensitic transformation temperature, the sputtering time and applied power were adjusted. Accordingly, martensitic Cu-14Al-4Ni (wt. %) and Cu-13Al-5Ni (wt. %) thin films and austenitic Cu-12Al-7Ni (wt. %) thin films were obtained. In the latter, in situ heating during film growth led to austenitic Cu-12Al-7Ni (wt. %) thin films with a (200) textured growth as a result of the epitaxial relationship MgO(001)[100]/Cu-Al-Ni(001)[110]. Resistance versus temperature measurements were carried out to investigate the shape memory behavior of the austenitic Cu-12Al-7Ni (wt. %) thin films produced from the two approaches. While no signs of martensitic transformation were detected in the quenched multilayered thin films, a trend that might be indicative of thermal hysteresis was encountered for the epitaxially grown thin films. In the present work, the differences in the crystallographic structure and the shape memory behavior of the Cu-Al-Ni thin films obtained by the two different preparation approaches are discussed.
Grants:	Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-292 Ministerio de Economía y Competitividad MAT2017-86357-C3-1-R Ministerio de Economía y Competitividad RYC-2012-10839 Ministerio de Economía y Competitividad IJCI-2015-27030 European Commission 642642
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Cu-Al-Ni ; Shape memory alloys ; Thin film ; Sputtering ; Size effects
Published in:	Coatings, Vol. 9, Issue 5 (May 2019) , art. 308, ISSN 2079-6412

DOI: 10.3390/coatings9050308

10 p, 3.0 MB

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