Details
Original language | English |
---|---|
Pages (from-to) | 587-599 |
Number of pages | 13 |
Journal | Acta materialia |
Volume | 54 |
Issue number | 3 |
Publication status | Published - Feb 2006 |
Externally published | Yes |
Abstract
The pseudoelastic responses of heat-treated CoNiAl single crystals with [0 0 1] and [1 1 5] orientations, multicrystals of nominally [1 2 3] orientation, and polycrystals are investigated under tension and compression stress states. The highest transformation strains are found under pseudoelasticity for the [0 0 1] orientation in tension and compression as 6.2% and 4.1% respectively. Experiments reveal tension-compression asymmetry of the critical transformation stress and of the stress hysteresis. The pseudoelastic stress-strain response is limited in tension to a much narrower temperature range than that in compression. The levels of strain recovery and the size of the stress hysteresis reveal the influence of dissipative mechanisms. A thermodynamics framework is proposed for describing the role of plastic flow and the internal stress fields on the stress hysteresis behavior. Single crystals exhibit considerable recovery compared to polycrystals and multicrystals. Extensive transmission electron microscopy results confirm the increased plastic flow at the austenite-martensite interfaces and in the secondary phase.
Keywords
- Critical stress, Ferromagnetic shape memory alloy, Phase transformation, Pseudoelasticity, Shape memory
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Materials Science(all)
- Ceramics and Composites
- Materials Science(all)
- Polymers and Plastics
- Materials Science(all)
- Metals and Alloys
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In: Acta materialia, Vol. 54, No. 3, 02.2006, p. 587-599.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Pseudoelasticity in Co-Ni-Al single and polycrystals
AU - Hamilton, R. F.
AU - Sehitoglu, H.
AU - Efstathiou, C.
AU - Maier, H. J.
AU - Chumlyakov, Y.
N1 - Funding Information: The work was supported by grants CMS-0428428, the National Science Foundation, Division of Civil and Mechanical Systems, and Deutsche Forschungsgemeinschaft (German portion of the work).
PY - 2006/2
Y1 - 2006/2
N2 - The pseudoelastic responses of heat-treated CoNiAl single crystals with [0 0 1] and [1 1 5] orientations, multicrystals of nominally [1 2 3] orientation, and polycrystals are investigated under tension and compression stress states. The highest transformation strains are found under pseudoelasticity for the [0 0 1] orientation in tension and compression as 6.2% and 4.1% respectively. Experiments reveal tension-compression asymmetry of the critical transformation stress and of the stress hysteresis. The pseudoelastic stress-strain response is limited in tension to a much narrower temperature range than that in compression. The levels of strain recovery and the size of the stress hysteresis reveal the influence of dissipative mechanisms. A thermodynamics framework is proposed for describing the role of plastic flow and the internal stress fields on the stress hysteresis behavior. Single crystals exhibit considerable recovery compared to polycrystals and multicrystals. Extensive transmission electron microscopy results confirm the increased plastic flow at the austenite-martensite interfaces and in the secondary phase.
AB - The pseudoelastic responses of heat-treated CoNiAl single crystals with [0 0 1] and [1 1 5] orientations, multicrystals of nominally [1 2 3] orientation, and polycrystals are investigated under tension and compression stress states. The highest transformation strains are found under pseudoelasticity for the [0 0 1] orientation in tension and compression as 6.2% and 4.1% respectively. Experiments reveal tension-compression asymmetry of the critical transformation stress and of the stress hysteresis. The pseudoelastic stress-strain response is limited in tension to a much narrower temperature range than that in compression. The levels of strain recovery and the size of the stress hysteresis reveal the influence of dissipative mechanisms. A thermodynamics framework is proposed for describing the role of plastic flow and the internal stress fields on the stress hysteresis behavior. Single crystals exhibit considerable recovery compared to polycrystals and multicrystals. Extensive transmission electron microscopy results confirm the increased plastic flow at the austenite-martensite interfaces and in the secondary phase.
KW - Critical stress
KW - Ferromagnetic shape memory alloy
KW - Phase transformation
KW - Pseudoelasticity
KW - Shape memory
UR - http://www.scopus.com/inward/record.url?scp=29844458875&partnerID=8YFLogxK
U2 - 10.1016/j.actamat.2005.09.025
DO - 10.1016/j.actamat.2005.09.025
M3 - Article
AN - SCOPUS:29844458875
VL - 54
SP - 587
EP - 599
JO - Acta materialia
JF - Acta materialia
SN - 1359-6454
IS - 3
ER -