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Proceedings Paper

Correlation between mechanical behavior and actuator-type performance of Ni-Ti-Pd high-temperature shape memory alloys
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Paper Abstract

High-temperature shape memory alloys in the NiTiPd system are being investigated as lower cost alternatives to NiTiPt alloys for use in compact solid-state actuators for the aerospace, automotive, and power generation industries. A range of ternary NiTiPd alloys containing 15 to 46 at.% Pd has been processed and actuator mimicking tests (thermal cycling under load) were used to measure transformation temperatures, work behavior, and dimensional stability. With increasing Pd content, the work output of the material decreased, while the amount of permanent strain resulting from each load-biased thermal cycle increased. Monotonic isothermal tension testing of the high-temperature austenite and low temperature martensite phases was used to partially explain these behaviors, where a mismatch in yield strength between the austenite and martensite phases was observed at high Pd levels. Moreover, to further understand the source of the permanent strain at lower Pd levels, strain recovery tests were conducted to determine the onset of plastic deformation in the martensite phase. Consequently, the work behavior and dimensional stability during thermal cycling under load of the various NiTiPd alloys is discussed in relation to the deformation behavior of the materials as revealed by the strain recovery and monotonic tension tests.

Paper Details

Date Published: 20 April 2007
PDF: 12 pages
Proc. SPIE 6526, Behavior and Mechanics of Multifunctional and Composite Materials 2007, 65262B (20 April 2007); doi: 10.1117/12.715252
Show Author Affiliations
Glen S. Bigelow, NASA Glenn Research Ctr. (United States)
Santo A. Padula, NASA Glenn Research Ctr. (United States)
Anita Garg, Univ. of Toledo (United States)
NASA Glenn Research Ctr. (United States)
Ronald D. Noebe, NASA Glenn Research Ctr. (United States)


Published in SPIE Proceedings Vol. 6526:
Behavior and Mechanics of Multifunctional and Composite Materials 2007
Marcelo J. Dapino, Editor(s)

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