Applications of shape memory alloys: advantages, disadvantages, and limitations

A. David Johnson; Valery Martynov; Vikas Gupta

doi:10.1117/12.442964

28 September 2001 Applications of shape memory alloys: advantages, disadvantages, and limitations

A. David Johnson, Valery Martynov, Vikas Gupta

Proceedings Volume 4557, Micromachining and Microfabrication Process Technology VII; (2001) https://doi.org/10.1117/12.442964
Event: Micromachining and Microfabrication, 2001, San Francisco, CA, United States

Abstract

Titanium-nickel (TiNi) based shape memory alloys (SMAs) are used in a wide range of applications. They are especially practical as thin film actuators because of the large work output per unit of actuator mass and ability for rapid thermal cycling due to large surface to volume ratio. Sputter deposited thin TiNi film has been developed for use in miniature actuators for microvalves, microrelays, optical switches and also for building small implantable medical devices. Chemical composition of the deposited SMA must be held within close limits and for the film to have shape memory properties a crystallization anneal is required. To avoid flaws in film quality the surface on which SMA is deposited has to meet certain criteria. Basic MEMS processes (photolithography and chemical etching) are used for device fabrication. Although TiNi is resistant to most chemicals, some acids used in MEMS can damage it. Thus, selection of processes and reagents compatible with TiNi requires care and experimentation. This paper discusses some applications of SMA thin films along with experience gained in bringing device s to production readiness. It illustrates simple design rules for incorporating shape memory microactuators in MEMS devices and describes some of the pitfalls to be avoided.

Citation Download Citation

A. David Johnson, Valery Martynov, and Vikas Gupta "Applications of shape memory alloys: advantages, disadvantages, and limitations", Proc. SPIE 4557, Micromachining and Microfabrication Process Technology VII, (28 September 2001); https://doi.org/10.1117/12.442964

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available