Details
| Original language | English |
|---|---|
| Pages (from-to) | 6-17 |
| Number of pages | 12 |
| Journal | Shape Memory and Superelasticity |
| Volume | 1 |
| Issue number | 1 |
| Publication status | Published - 21 Apr 2015 |
Abstract
Conventional shape memory alloys cannot be employed for applications in the elevated temperature regime due to rapid functional degradation. Co–Ni–Ga has shown the potential to be used up to temperatures of about 400 °C due to a fully reversible superelastic stress–strain response. However, available results only highlight the superelastic response for single cycle tests. So far, no data addressing cyclic loading and functional fatigue are available. In order to close this gap, the current study reports on the cyclic degradation behavior and tension–compression asymmetry in [001]-oriented Co49Ni21Ga30 single crystals at elevated temperatures. The cyclic stress-strain response of the material under displacement controlled superelastic loading conditions was found to be dictated by the number of active martensite variants and different resulting stabilization effects. Co–Ni–Ga shows a large superelastic temperature window of about 400 °C under tension and compression, but a linear Clausius–Clapeyron relationship could only be observed up to a temperature of 200 °C. In the present experiments, the samples were subjected to 1000 cycles at different temperatures. Degradation mechanisms were characterized by neutron diffraction and transmission electron microscopy. The results in this study confirm the potential of these alloys for damping applications at elevated temperatures.
Keywords
- Internal friction, Martensite stabilization, Martensitic phase transformation, Shape memory alloy (SMA), Superelasticity
ASJC Scopus subject areas
- Materials Science(all)
- General Materials Science
- Engineering(all)
- Mechanics of Materials
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In: Shape Memory and Superelasticity, Vol. 1, No. 1, 21.04.2015, p. 6-17.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Functional Fatigue and Tension–Compression Asymmetry in [001]-Oriented Co49Ni21Ga30 High-Temperature Shape Memory Alloy Single Crystals
AU - Krooß, P.
AU - Niendorf, T.
AU - Kadletz, P. M.
AU - Somsen, C.
AU - Gutmann, M. J.
AU - Chumlyakov, Y. I.
AU - Schmahl, W. W.
AU - Eggeler, G.
AU - Maier, H. J.
N1 - Funding information: Financial support by the Deutsche Forschungsgemeinschaft (DFG) within the Research Unit Program “Hochtemperatur-Formgedächtnislegierungen” (Contract Nos. NI1327/3-1; MA1175/34-1; SCHM930/13-1 and EG101/22-1) is gratefully acknowledged.
PY - 2015/4/21
Y1 - 2015/4/21
N2 - Conventional shape memory alloys cannot be employed for applications in the elevated temperature regime due to rapid functional degradation. Co–Ni–Ga has shown the potential to be used up to temperatures of about 400 °C due to a fully reversible superelastic stress–strain response. However, available results only highlight the superelastic response for single cycle tests. So far, no data addressing cyclic loading and functional fatigue are available. In order to close this gap, the current study reports on the cyclic degradation behavior and tension–compression asymmetry in [001]-oriented Co49Ni21Ga30 single crystals at elevated temperatures. The cyclic stress-strain response of the material under displacement controlled superelastic loading conditions was found to be dictated by the number of active martensite variants and different resulting stabilization effects. Co–Ni–Ga shows a large superelastic temperature window of about 400 °C under tension and compression, but a linear Clausius–Clapeyron relationship could only be observed up to a temperature of 200 °C. In the present experiments, the samples were subjected to 1000 cycles at different temperatures. Degradation mechanisms were characterized by neutron diffraction and transmission electron microscopy. The results in this study confirm the potential of these alloys for damping applications at elevated temperatures.
AB - Conventional shape memory alloys cannot be employed for applications in the elevated temperature regime due to rapid functional degradation. Co–Ni–Ga has shown the potential to be used up to temperatures of about 400 °C due to a fully reversible superelastic stress–strain response. However, available results only highlight the superelastic response for single cycle tests. So far, no data addressing cyclic loading and functional fatigue are available. In order to close this gap, the current study reports on the cyclic degradation behavior and tension–compression asymmetry in [001]-oriented Co49Ni21Ga30 single crystals at elevated temperatures. The cyclic stress-strain response of the material under displacement controlled superelastic loading conditions was found to be dictated by the number of active martensite variants and different resulting stabilization effects. Co–Ni–Ga shows a large superelastic temperature window of about 400 °C under tension and compression, but a linear Clausius–Clapeyron relationship could only be observed up to a temperature of 200 °C. In the present experiments, the samples were subjected to 1000 cycles at different temperatures. Degradation mechanisms were characterized by neutron diffraction and transmission electron microscopy. The results in this study confirm the potential of these alloys for damping applications at elevated temperatures.
KW - Internal friction
KW - Martensite stabilization
KW - Martensitic phase transformation
KW - Shape memory alloy (SMA)
KW - Superelasticity
UR - http://www.scopus.com/inward/record.url?scp=85070923300&partnerID=8YFLogxK
U2 - 10.1007/s40830-015-0003-6
DO - 10.1007/s40830-015-0003-6
M3 - Article
AN - SCOPUS:85070923300
VL - 1
SP - 6
EP - 17
JO - Shape Memory and Superelasticity
JF - Shape Memory and Superelasticity
SN - 2199-384X
IS - 1
ER -