Details
| Original language | English |
|---|---|
| Pages (from-to) | 979-985 |
| Number of pages | 7 |
| Journal | Scripta materialia |
| Volume | 51 |
| Issue number | 10 |
| Publication status | Published - Nov 2004 |
| Externally published | Yes |
Abstract
The stress-strain response of Co-Ni-Al with a two-phase microstructure displayed an unusual decrease in critical stress (84%) with strain or thermal cycling accompanied with an improved recoverability of pseudoelastic and shape memory strains. The pronounced decrease in critical stress occurred over a wide temperature range (145°C), and is linked to the interaction of the transformation front with a secondary phase and the residual martensitic domains. The stabilized material is better suited for magnetic shape memory applications because of the lower elastic strain energy manifested through the lower critical stress and the reduced apparent elastic modulus. An extensive experimental program was utilized to establish the Clausius-Clapeyron relationship and the temperature dependence of critical stress for slip at elevated temperatures. A reduction of a factor of two in the slope of the Clausius-Clapeyron curve for the repeatedly deformed material was measured commensurate with the reduction in critical stress. The repeated deformation also produced a decrease in stress hysteresis and a reduction in residual strain making this material rather attractive for shape memory applications.
Keywords
- Critical stress, Ferromagnetic shape memory alloy, Hysteresis, Phase transformation, Pseudoelasticity, Shape memory
ASJC Scopus subject areas
- Materials Science(all)
- General Materials Science
- Physics and Astronomy(all)
- Condensed Matter Physics
- Engineering(all)
- Mechanics of Materials
- Engineering(all)
- Mechanical Engineering
- Materials Science(all)
- Metals and Alloys
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In: Scripta materialia, Vol. 51, No. 10, 11.2004, p. 979-985.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Large reduction in critical stress in co-ni-al upon repeated transformation
AU - Efstathiou, C.
AU - Sehitoglu, H.
AU - Johnson, A. J.Wagoner
AU - Hamilton, R. F.
AU - Maier, H. J.
AU - Chumlyakov, Y.
N1 - Funding Information: The work is supported partially by the AFOSR, Directorate of Aerospace and Materials Sciences and NSF grants CMS-0332824 and CMS-0428428. H.J. Maier acknowledges the support of Deutsche Forschungsgemeinschaft.
PY - 2004/11
Y1 - 2004/11
N2 - The stress-strain response of Co-Ni-Al with a two-phase microstructure displayed an unusual decrease in critical stress (84%) with strain or thermal cycling accompanied with an improved recoverability of pseudoelastic and shape memory strains. The pronounced decrease in critical stress occurred over a wide temperature range (145°C), and is linked to the interaction of the transformation front with a secondary phase and the residual martensitic domains. The stabilized material is better suited for magnetic shape memory applications because of the lower elastic strain energy manifested through the lower critical stress and the reduced apparent elastic modulus. An extensive experimental program was utilized to establish the Clausius-Clapeyron relationship and the temperature dependence of critical stress for slip at elevated temperatures. A reduction of a factor of two in the slope of the Clausius-Clapeyron curve for the repeatedly deformed material was measured commensurate with the reduction in critical stress. The repeated deformation also produced a decrease in stress hysteresis and a reduction in residual strain making this material rather attractive for shape memory applications.
AB - The stress-strain response of Co-Ni-Al with a two-phase microstructure displayed an unusual decrease in critical stress (84%) with strain or thermal cycling accompanied with an improved recoverability of pseudoelastic and shape memory strains. The pronounced decrease in critical stress occurred over a wide temperature range (145°C), and is linked to the interaction of the transformation front with a secondary phase and the residual martensitic domains. The stabilized material is better suited for magnetic shape memory applications because of the lower elastic strain energy manifested through the lower critical stress and the reduced apparent elastic modulus. An extensive experimental program was utilized to establish the Clausius-Clapeyron relationship and the temperature dependence of critical stress for slip at elevated temperatures. A reduction of a factor of two in the slope of the Clausius-Clapeyron curve for the repeatedly deformed material was measured commensurate with the reduction in critical stress. The repeated deformation also produced a decrease in stress hysteresis and a reduction in residual strain making this material rather attractive for shape memory applications.
KW - Critical stress
KW - Ferromagnetic shape memory alloy
KW - Hysteresis
KW - Phase transformation
KW - Pseudoelasticity
KW - Shape memory
UR - http://www.scopus.com/inward/record.url?scp=4444331904&partnerID=8YFLogxK
U2 - 10.1016/j.scriptamat.2004.07.014
DO - 10.1016/j.scriptamat.2004.07.014
M3 - Article
AN - SCOPUS:4444331904
VL - 51
SP - 979
EP - 985
JO - Scripta materialia
JF - Scripta materialia
SN - 1359-6462
IS - 10
ER -