Title: Thin film shape memory alloys and microactuators

Authors: Y.Q. Fu, J.K. Luo, A.J. Flewitt, W.M. Huang, S. Zhang, H.J. Du, W.I. Milne

Addresses: Department of Mechanical Engineering, School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh EH14 4AS, UK. ' Centre for Material Research and Innovation, University of Bolton, Deane Road, Bolton BL3 5AB, UK. ' Centre for Advanced Photonics and Electronics, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK. ' School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798. ' School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798. ' School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798. ' Centre for Advanced Photonics and Electronics, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK

Abstract: For Micro-electro-mechanical System (MEMS) applications, TiNi-based thin film Shape Memory Alloys (SMAs) possess many desirable properties, such as high power density, large transformation stress and strain upon heating and cooling, superelasticity and biocompatibility. In this paper, recent development in TiNi-based thin film SMA and microactuator applications is discussed. The topics related to film deposition and characterisation is mainly focused on crystal nucleation and growth during annealing, film thickness effect, film texture, stress induced surface relief, wrinkling and trenches as well as Temperature Memory Effect (TME). The microactuator applications are mainly focused on microvalve and microcage for biological applications, micromirror for optical applications and data storage using nanoindentation method.

Keywords: shape memory alloys; thin film SMA; microactuators; TiNi; titanium nickel; thin films; MEMS; microelectromechanical systems; MEMS; film deposition; characterisation; crystal nucleation; film thickness; film texture; stress; surface relief; wrinkling; temperature memory effect; TME; microvalves; microcages; micromirrors; nanoindentation.

DOI: 10.1504/IJCMSSE.2009.027483

International Journal of Computational Materials Science and Surface Engineering, 2009 Vol.2 No.3/4, pp.208 - 226

Published online: 28 Jul 2009 *

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