Brittle-ductile behavior of a nanocrack in nanocrystalline Ni： A quasicontinuum study

The effects of stacking fault energy, unstable stacking fault energy, and unstable twinning fault energy on the fracture behavior of nanocrystalline Ni are studied via quasicontinuum simulations. Two semi-empirical potentials for Ni are used to vary the values of these generalized planar fault energ...

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Bibliographic Details
Published in	Chinese physics B Vol. 21; no. 9; pp. 196 - 203
Main Author	邵宇飞杨鑫赵星王绍青
Format	Journal Article
Language	English
Published	01.09.2012
Subjects	Ductile brittle transition Faults Fracture mechanics Fracture toughness Nanocrystals Nanostructure Nickel Stacking fault energy Twinning 不稳定准连续堆垛层错能断裂行为断裂韧性纳米晶面心立方金属
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ISSN	1674-1056 2058-3834 1741-4199
DOI	10.1088/1674-1056/21/9/093104

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Summary:	The effects of stacking fault energy, unstable stacking fault energy, and unstable twinning fault energy on the fracture behavior of nanocrystalline Ni are studied via quasicontinuum simulations. Two semi-empirical potentials for Ni are used to vary the values of these generalized planar fault energies. When the above three energies are reduced, a brittle-to-ductile transition of the fracture behavior is observed. In the model with higher generalized planar fault energies, a nanocrack proceeds along a grain boundary, while in the model with lower energies, the tip of the nanocrack becomes blunt. A greater twinning tendency is also observed in the more ductile model. These results indicate that the fracture toughness of nanocrystalline face-centered-cubic metals and alloys might be efficiently improved by controlling the generalized planar fault energies.
Bibliography:	atomistic simulations, nanocrystalline materials, fracture, grain boundaries The effects of stacking fault energy, unstable stacking fault energy, and unstable twinning fault energy on the fracture behavior of nanocrystalline Ni are studied via quasicontinuum simulations. Two semi-empirical potentials for Ni are used to vary the values of these generalized planar fault energies. When the above three energies are reduced, a brittle-to-ductile transition of the fracture behavior is observed. In the model with higher generalized planar fault energies, a nanocrack proceeds along a grain boundary, while in the model with lower energies, the tip of the nanocrack becomes blunt. A greater twinning tendency is also observed in the more ductile model. These results indicate that the fracture toughness of nanocrystalline face-centered-cubic metals and alloys might be efficiently improved by controlling the generalized planar fault energies. 11-5639/O4 Shao Yu-Fei, Yang Xin, Zhao Xing, and Wang Shao-Qing a） Institute of Applied Physics and Technology, Department of General Studies, Liaoning Technical University, Huludao 125105, China b） Department of Mathematics and Physics, Liaoning University of Technology, Jinzhou 121001, China c） Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences Shenyang 110016, China ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1674-1056 2058-3834 1741-4199
DOI:	10.1088/1674-1056/21/9/093104