Details
| Original language | English |
|---|---|
| Pages (from-to) | 5893-5904 |
| Number of pages | 12 |
| Journal | Acta materialia |
| Volume | 59 |
| Issue number | 15 |
| Publication status | Published - 24 Jun 2011 |
| Externally published | Yes |
Abstract
This work elucidates the details of twinning in martensite as the major deformation mode in NiTi undergoing thermoelastic phase transformation. We report on generalized planar fault energy and generalized stacking fault energy barriers in NiTi shape memory alloys in the monoclinic martensite state (B19′). The energy barrier for (0 0 1) twin migration is 7.6 mJ m -2, which is smaller than that for twinning in soft face-centered cubic metals. The conjugate (1 0 0) twinning corresponds to a higher energy barrier of 41 mJ m-2. Both modes of twinning have been observed experimentally, the (0 0 1) at lower stresses, and the (1 0 0) mode at higher stresses. The unstable stacking fault energy for slip is also calculated, and the results show that twin migration is favored over slip in the B19′ state. We suggest that the results provide a quantitative methodology for the development of new shape memory alloys in which twinning can occur at stress levels far below that corresponding to plastic deformation.
Keywords
- Ab initio, Energetics, Martensite, NiTi, Twinning
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. 59, No. 15, 24.06.2011, p. 5893-5904.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Energetics of twinning in martensitic NiTi
AU - Ezaz, T.
AU - Sehitoglu, H.
AU - Maier, H. J.
N1 - Funding information: The work was supported by the NSF grant DMR-08-03270 and partly by CMMI-09-26813.
PY - 2011/6/24
Y1 - 2011/6/24
N2 - This work elucidates the details of twinning in martensite as the major deformation mode in NiTi undergoing thermoelastic phase transformation. We report on generalized planar fault energy and generalized stacking fault energy barriers in NiTi shape memory alloys in the monoclinic martensite state (B19′). The energy barrier for (0 0 1) twin migration is 7.6 mJ m -2, which is smaller than that for twinning in soft face-centered cubic metals. The conjugate (1 0 0) twinning corresponds to a higher energy barrier of 41 mJ m-2. Both modes of twinning have been observed experimentally, the (0 0 1) at lower stresses, and the (1 0 0) mode at higher stresses. The unstable stacking fault energy for slip is also calculated, and the results show that twin migration is favored over slip in the B19′ state. We suggest that the results provide a quantitative methodology for the development of new shape memory alloys in which twinning can occur at stress levels far below that corresponding to plastic deformation.
AB - This work elucidates the details of twinning in martensite as the major deformation mode in NiTi undergoing thermoelastic phase transformation. We report on generalized planar fault energy and generalized stacking fault energy barriers in NiTi shape memory alloys in the monoclinic martensite state (B19′). The energy barrier for (0 0 1) twin migration is 7.6 mJ m -2, which is smaller than that for twinning in soft face-centered cubic metals. The conjugate (1 0 0) twinning corresponds to a higher energy barrier of 41 mJ m-2. Both modes of twinning have been observed experimentally, the (0 0 1) at lower stresses, and the (1 0 0) mode at higher stresses. The unstable stacking fault energy for slip is also calculated, and the results show that twin migration is favored over slip in the B19′ state. We suggest that the results provide a quantitative methodology for the development of new shape memory alloys in which twinning can occur at stress levels far below that corresponding to plastic deformation.
KW - Ab initio
KW - Energetics
KW - Martensite
KW - NiTi
KW - Twinning
UR - http://www.scopus.com/inward/record.url?scp=79961013530&partnerID=8YFLogxK
U2 - 10.1016/j.actamat.2011.05.063
DO - 10.1016/j.actamat.2011.05.063
M3 - Article
AN - SCOPUS:79961013530
VL - 59
SP - 5893
EP - 5904
JO - Acta materialia
JF - Acta materialia
SN - 1359-6454
IS - 15
ER -