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

作　　者：邵宇飞 杨鑫 赵星 王绍青 

机构地区：[1]Institute of Applied Physics and Technology,Department of General Studies,Liaoning Technical University [2]Department of Mathematics and Physics,Liaoning University of Technology [3]Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences

出　　处：《Chinese Physics B》2012年第9期196-203,共8页中国物理B（英文版）

基　　金：Project supported by the National Basic Research Program of China (Grant No. 2011CB606403)

摘　　要：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.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.

关 键 词：atomistic simulations nanocrystalline materials FRACTURE grain boundaries 

分 类 号：TB383.1[一般工业技术—材料科学与工程]