Shape Memory Alloys for small scale actuation

Shape Memory Alloys (SMAs), materials that can undergo a fully recoverable strain change due to a thermal cycle, and which can be produced in a form that is superelastic are only utilized limitedly. In this thesis, I investigated the relationship between the material properties of shape memory alloy micro-wires and their mechanical performance. This study was conducted with two main types of SMAs, the first a commercially available NiTi wire, and the second an emerging Cu-based alternative. This comparison allows an understanding of the current state of the art for small scale actuation with SMA wires, and to evaluate the Cu-based alternative SMA, which has a reduced cost and improved thermal properties. This thesis evaluates Cu-based SMAs as substitutes for NiTi in terms of activation strain of wire during a shape memory cycle, power consumption during actuation, heating and cooling times during actuation, and cost. Furthermore this thesis includes studies on the processing of Cu-based alternatives to enhance shape memory properties of interests, such as transformation temperature and fatigue, and suggests future work to improve Cu-based SMA wires..

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2018

Author dc:creator

• Hartwell, Ashley (Ashley Jessica)

Advisor dc:contributor.advisor

• Christopher A. Schuh and Ken Kamrin.

• Mechanical Engineering.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/118714

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/118714