Reversible surface morphology in shape-memory alloy thin films

Wu, M. J., Huang, Wei Min, Fu, Yong Qing, Chollet, F., Hu, Yue and Cai, M. (2009) Reversible surface morphology in shape-memory alloy thin films. Journal of Applied Physics, 105 (3). 033517. ISSN 0021 8979

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Abstract

Reversible surface morphology can be used for significantly changing many surface properties such as roughness, friction, reflection, surface tension, etc. However, it is not easy to realize atop metals at micron scale around ambient temperature. In this paper, we demonstrate that TiNi and TiNi based (e.g., TiNiCu) shape-memorythin films, which are sputter-deposited atop a silicon wafer, may have different types of thermally-induced reversible surface morphologies. Apart from the well-known surface relief phenomenon, irregular surface trenches may appear in the fully crystallized thin films, but disappear upon heating. On the other hand, in partially crystallized thin films, the crystalline structures (islands) appear in chrysanthemum-shape at high temperature; while at room temperature, the surface morphology within the islands changes to standard martensite striations. Both phenomena are fully repeatable upon thermal cycling. The mechanisms behind these phenomena are investigated.

Item Type:	Article
Subjects:	F200 Materials Science
Department:	Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User:	Becky Skoyles
Date Deposited:	23 Mar 2015 10:10
Last Modified:	12 Oct 2019 19:06
URI:	http://nrl.northumbria.ac.uk/id/eprint/21666

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