Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 547-552 |
| Seitenumfang | 6 |
| Fachzeitschrift | Zeitschrift fuer Metallkunde/Materials Research and Advanced Techniques |
| Jahrgang | 94 |
| Ausgabenummer | 5 |
| Publikationsstatus | Veröffentlicht - Mai 2003 |
| Extern publiziert | Ja |
Abstract
The structural evolution in NiTi shape memory alloys subjected to pseudoelastic cycling is examined in the present study. Single crystals with [100] and [111] orientations were subjected to repeated compressive cycles and then studied by transmission electron microscopy (TEM). TEM observations were made at cycle numbers 1, 2, 5, 10, and 20 since the majority of degradation occurs during these initial cycle numbers. Under compression, single crystals with [111] orientations degraded much faster than crystals with [100] orientations. Under tension, single crystals with [100] orientations fractured in the elastic region, and crystals with [111] orientations showed considerable degradation as a function of cycling. Intermittent TEM observations on single crystals oriented along the [111] direction showed an increase in dislocation density on multiple active slip systems as a function of cycling. Single crystals oriented along the [100] orientation show a less dramatic increase in dislocation density as a function of cycling. TEM observations have revealed that dislocation structures formed near martensite plates have a similar periodicity as internal twin modes within the martensite. This observation implies that, although the interface between the martensite and parent phase is a low-energy boundary, the local disruptions due to internal twins create preferential nucleation sites for the formation of lattice defects.
ASJC Scopus Sachgebiete
- Physik und Astronomie (insg.)
- Physik der kondensierten Materie
- Chemie (insg.)
- Physikalische und Theoretische Chemie
- Werkstoffwissenschaften (insg.)
- Metalle und Legierungen
- Werkstoffwissenschaften (insg.)
- Werkstoffchemie
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in: Zeitschrift fuer Metallkunde/Materials Research and Advanced Techniques, Jahrgang 94, Nr. 5, 05.2003, S. 547-552.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Structural evolution during the cycling of NiTi shape memory alloys
AU - Hurley, Jay
AU - Ortega, Alicia M.
AU - Lechniak, Jason
AU - Gall, Ken
AU - Maier, Hans J.
PY - 2003/5
Y1 - 2003/5
N2 - The structural evolution in NiTi shape memory alloys subjected to pseudoelastic cycling is examined in the present study. Single crystals with [100] and [111] orientations were subjected to repeated compressive cycles and then studied by transmission electron microscopy (TEM). TEM observations were made at cycle numbers 1, 2, 5, 10, and 20 since the majority of degradation occurs during these initial cycle numbers. Under compression, single crystals with [111] orientations degraded much faster than crystals with [100] orientations. Under tension, single crystals with [100] orientations fractured in the elastic region, and crystals with [111] orientations showed considerable degradation as a function of cycling. Intermittent TEM observations on single crystals oriented along the [111] direction showed an increase in dislocation density on multiple active slip systems as a function of cycling. Single crystals oriented along the [100] orientation show a less dramatic increase in dislocation density as a function of cycling. TEM observations have revealed that dislocation structures formed near martensite plates have a similar periodicity as internal twin modes within the martensite. This observation implies that, although the interface between the martensite and parent phase is a low-energy boundary, the local disruptions due to internal twins create preferential nucleation sites for the formation of lattice defects.
AB - The structural evolution in NiTi shape memory alloys subjected to pseudoelastic cycling is examined in the present study. Single crystals with [100] and [111] orientations were subjected to repeated compressive cycles and then studied by transmission electron microscopy (TEM). TEM observations were made at cycle numbers 1, 2, 5, 10, and 20 since the majority of degradation occurs during these initial cycle numbers. Under compression, single crystals with [111] orientations degraded much faster than crystals with [100] orientations. Under tension, single crystals with [100] orientations fractured in the elastic region, and crystals with [111] orientations showed considerable degradation as a function of cycling. Intermittent TEM observations on single crystals oriented along the [111] direction showed an increase in dislocation density on multiple active slip systems as a function of cycling. Single crystals oriented along the [100] orientation show a less dramatic increase in dislocation density as a function of cycling. TEM observations have revealed that dislocation structures formed near martensite plates have a similar periodicity as internal twin modes within the martensite. This observation implies that, although the interface between the martensite and parent phase is a low-energy boundary, the local disruptions due to internal twins create preferential nucleation sites for the formation of lattice defects.
KW - Cyclic degradation
KW - Fatigue
KW - Microstructure
KW - NiTi shape memory alloys
KW - Single crystals
KW - Stress-strain response
UR - http://www.scopus.com/inward/record.url?scp=16544383705&partnerID=8YFLogxK
U2 - 10.3139/146.030547
DO - 10.3139/146.030547
M3 - Article
AN - SCOPUS:16544383705
VL - 94
SP - 547
EP - 552
JO - Zeitschrift fuer Metallkunde/Materials Research and Advanced Techniques
JF - Zeitschrift fuer Metallkunde/Materials Research and Advanced Techniques
SN - 0044-3093
IS - 5
ER -