The relationship between the microstructure and shape memory properties of -oriented Ni45.3Ti29.7Hf20Pd5 (at%) single crystals was explored. In this precipitation-strengthened alloy, the size and volume fraction of precipitates and interparticle distances govern the martensite morphology and the ensuing shape memory responses. Aging of the solution-treated material, leading to a microstructure of fine, closely spaced precipitates, resulted in a material capable of a shape memory strain of 2.15% at 1000 MPa in compression. Larger precipitates formed after aging the as-grown single crystals (without a prior solution treatment) resulting in a shape memory strain of 2.5% at this same stress level in constant-stress thermal cycling experiments. Superelastic strains of 4% in compression without any residual strain were possible under various microstructural conditions and the stress hysteresis could be varied between nearly 500 and 1000 MPa depending on the microstructure.
|Journal||Smart Materials and Structures|
|State||Published - Feb 22 2016|
Bibliographical noteFunding Information:
This work was supported in part by the NASA Transformative Aeronautics Concepts Program (TACP) under the Transformational Tools & Technologies Project, the NASA EPSCOR program under Grant NNX11AQ31A, KSEF-148- 502-15-355, NSF CMMI-1538665, RSF program under grant no. 14-29-00012 and Erciyes University.
© 2016 IOP Publishing Ltd.
- elastic energy storage
- shape memory alloys
ASJC Scopus subject areas
- Signal Processing
- Civil and Structural Engineering
- Atomic and Molecular Physics, and Optics
- Materials Science (all)
- Condensed Matter Physics
- Mechanics of Materials
- Electrical and Electronic Engineering