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Characterization of Ternary NiTiPd High-Temperature Shape-Memory Alloys under Load-Biased Thermal CyclingWhile NiTiPd alloys have been extensively studied for proposed use in high-temperature shape-memory applications, little is known about the shape-memory response of these materials under stress. Consequently, the isobaric thermal cyclic responses of five (Ni,Pd)49.5Ti50.5 alloys with constant stoichiometry and Pd contents ranging from 15 to 46 at. pct were investigated. From these tests, transformation temperatures, transformation strain (which is proportional to work output), and unrecovered strain per cycle (a measure of dimensional instability) were determined as a function of stress for each alloy. It was found that increasing the Pd content over this range resulted in a linear increase in transformation temperature, as expected. At a given stress level, work output decreased while the amount of unrecovered strain produced during each load-biased thermal cycle increased with increasing Pd content, during the initial thermal cycles. However, continued thermal cycling at constant stress resulted in a saturation of the work output and nearly eliminated further unrecovered strain under certain conditions, resulting in stable behavior amenable to many actuator applications.
Document ID
Document Type
Reprint (Version printed in journal)
Bigelow, Glen S. (NASA Glenn Research Center Cleveland, OH, United States)
Padula, Santo A. (NASA Glenn Research Center Cleveland, OH, United States)
Noebe, Ronald D. (NASA Glenn Research Center Cleveland, OH, United States)
Garg, Anita (Toledo Univ. Toledo, OH, United States)
Gaydosh, Darrell (Ohio Aerospace Inst. Cleveland, OH, United States)
Date Acquired
August 25, 2013
Publication Date
December 1, 2010
Publication Information
Publication: Metallurgical and Materials Transactions A
Volume: 41A
Subject Category
Metals and Metallic Materials
Report/Patent Number
Funding Number(s)
WBS: WBS 561581.
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