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Steps and [formula omitted] secondary twinning associated with [formula omitted] twin in titanium.
- Source :
-
Acta Materialia . Feb2019, Vol. 164, p776-787. 12p. - Publication Year :
- 2019
-
Abstract
- Abstract { 11 2 ¯ 2 } twinning commonly takes place in α-titanium (α-Ti). High-resolution transmission electron microscopies (HRTEM) explored various steps along { 11 2 ¯ 2 } coherent twin boundary. Topological model of { 11 2 ¯ 2 } twin revealed twinning disconnections (TDs) that are represented by ( b i , i h { 11 2 ¯ 2 } ) corresponding to a step height i h { 11 2 ¯ 2 } and a shear vector b i. Atomistic simulations were conducted to study the energies and kinetics of TDs. Combining microscopies and atomistic simulations, we concluded that ( b 3 , 3 h { 11 2 ¯ 2 } ) is the elementary TD and ( b 1 , h { 11 2 ¯ 2 } ) is the reassembly TD. Steps observed in HRTEM thus can be treated as a reassembly of ( b 3 , 3 h { 11 2 ¯ 2 } ) TDs and ( b 1 , h { 11 2 ¯ 2 } ) TDs. In addition, Electron Backscatter Diffraction (EBSD) maps revealed { 11 2 ¯ 2 } → { 11 2 ¯ 1 } double twins in α-Ti. Using two-dimensional and three-dimensional atomistic simulations, we demonstrated the nucleation of ( b 1 , h { 11 2 ¯ 2 } ) TD and { 11 2 ¯ 2 } → { 11 2 ¯ 1 } double twin through the interaction between basal < a > dislocation and { 11 2 ¯ 2 } twin. Our results enrich the understanding of { 11 2 ¯ 2 } twinning including TDs, steps, and { 11 2 ¯ 1 } secondary twins in hexagonal metals. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 13596454
- Volume :
- 164
- Database :
- Academic Search Index
- Journal :
- Acta Materialia
- Publication Type :
- Academic Journal
- Accession number :
- 133684795
- Full Text :
- https://doi.org/10.1016/j.actamat.2018.11.019