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High‐Temperature Shape Memory Effect in Ti‐Ta Thin Films Sputter Deposited at Room Temperature
Author(s) -
Motemani Y.,
Buenconsejo P. J. S.,
Craciunescu C.,
Ludwig A.
Publication year - 2014
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201400019
Subject(s) - materials science , shape memory alloy , thin film , orthorhombic crystal system , substrate (aquarium) , diffusionless transformation , sputtering , sputter deposition , martensite , composite material , phase (matter) , fabrication , nanotechnology , microstructure , crystallography , crystal structure , medicine , chemistry , oceanography , alternative medicine , organic chemistry , pathology , geology
Ti‐Ta based alloys are potential high‐temperature shape memory materials with operation temperatures above 100 °C. In this study, the room temperature fabrication of Ti‐Ta thin films showing a reversible martensitic transformation and a high temperature shape memory effect above 200 °C is reported. In contrast to other shape memory thin films, no further heat treatment is necessary to obtain the functional properties. A disordered α″ martensite (orthorhombic) phase is formed in the as‐deposited co‐sputtered Ti 70 Ta 30 , Ti 68 Ta 32 and Ti 67 Ta 33 films, independent of the substrate. A Ti 70 Ta 30 free‐standing film shows a reversible martensitic transformation, as confirmed by temperature–dependent XRD measurements during thermal cycling between 125 °C to 275 °C. Furthermore, a one‐way shape memory effect is qualitatively confirmed in this film. The observed properties of the Ti‐Ta thin films make them promising for applications on polymer substrates and especially in microsystem technologies.