Details
| Original language | English |
|---|---|
| Pages (from-to) | 339-348 |
| Number of pages | 10 |
| Journal | Acta materialia |
| Volume | 60 |
| Issue number | 1 |
| Publication status | Published - 4 Nov 2011 |
| Externally published | Yes |
Abstract
The (1 1 4) twin growth in the austenitic regime in NiTi (B2 lattice) is characterized precisely at the atomistic scale. This twinning mode is consistent with experimental observations but has not been well understood despite its importance. Combined shears, shuffles and interface shifts operate in a complex way to generate the (1 1 4) twin. Pure shear on the (1 1 4) plane results in a "pseudo-twin", and interchange shuffles are necessary to convert this to a "reflective" twin and render a lower energy state. Additional atomic shifts at the twin-matrix interfaces result in "sharp" boundaries, further lowering the energy barriers. We established the energy barrier to be 148 mJ m-2 during (114)[221̄] twin boundary growth of four layers at a time. The entire potential energy surface and the mean energy path during twinning can be derived from our simulations, providing the required insight into the atomistic processes involved.
Keywords
- (1 1 4) shuffle, ab initio, B2 NiTi, Deformation 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. 60, No. 1, 04.11.2011, p. 339-348.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Energetics of (1 1 4) twinning in B2 NiTi under coupled shear and shuffle
AU - Ezaz, Tawhid
AU - Sehitoglu, Huseyin
AU - Maier, Hans Jürgen
N1 - Funding information: The work is supported by the National Science Foundation under DMR-0803270. We acknowledge earlier discussions with Prof. D.D. Johnson on PES. The authors gratefully acknowledge the use of the parallel computing resources part of the Taub cluster provided by the Computational Science and Engineering Program at the University of Illinois, and also partial support from CMMI-1130031.
PY - 2011/11/4
Y1 - 2011/11/4
N2 - The (1 1 4) twin growth in the austenitic regime in NiTi (B2 lattice) is characterized precisely at the atomistic scale. This twinning mode is consistent with experimental observations but has not been well understood despite its importance. Combined shears, shuffles and interface shifts operate in a complex way to generate the (1 1 4) twin. Pure shear on the (1 1 4) plane results in a "pseudo-twin", and interchange shuffles are necessary to convert this to a "reflective" twin and render a lower energy state. Additional atomic shifts at the twin-matrix interfaces result in "sharp" boundaries, further lowering the energy barriers. We established the energy barrier to be 148 mJ m-2 during (114)[221̄] twin boundary growth of four layers at a time. The entire potential energy surface and the mean energy path during twinning can be derived from our simulations, providing the required insight into the atomistic processes involved.
AB - The (1 1 4) twin growth in the austenitic regime in NiTi (B2 lattice) is characterized precisely at the atomistic scale. This twinning mode is consistent with experimental observations but has not been well understood despite its importance. Combined shears, shuffles and interface shifts operate in a complex way to generate the (1 1 4) twin. Pure shear on the (1 1 4) plane results in a "pseudo-twin", and interchange shuffles are necessary to convert this to a "reflective" twin and render a lower energy state. Additional atomic shifts at the twin-matrix interfaces result in "sharp" boundaries, further lowering the energy barriers. We established the energy barrier to be 148 mJ m-2 during (114)[221̄] twin boundary growth of four layers at a time. The entire potential energy surface and the mean energy path during twinning can be derived from our simulations, providing the required insight into the atomistic processes involved.
KW - (1 1 4) shuffle
KW - ab initio
KW - B2 NiTi
KW - Deformation twinning
UR - http://www.scopus.com/inward/record.url?scp=80155211129&partnerID=8YFLogxK
U2 - 10.1016/j.actamat.2011.09.032
DO - 10.1016/j.actamat.2011.09.032
M3 - Article
AN - SCOPUS:80155211129
VL - 60
SP - 339
EP - 348
JO - Acta materialia
JF - Acta materialia
SN - 1359-6454
IS - 1
ER -