中国物理B ›› 2009, Vol. 18 ›› Issue (1): 251-258.doi: 10.1088/1674-1056/18/1/041

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Dislocation formation and twinning from the crack tip in Ni3Al: molecular dynamics simulations

谢红献1, 于涛1, 杜俊平1, 王崇愚2   

  1. (1)Central Iron and Steel Research Institute, Beijing 100081, China; (2)Central Iron and Steel Research Institute, Beijing 100081, China;International Centre for Materials Physics, Chinese Academy of Sciences, Shenyang 110016, China;Department of Physics, Tsinghua University, Beijing 100084, China
  • 收稿日期:2008-06-29 修回日期:2008-08-20 出版日期:2009-01-20 发布日期:2009-01-20
  • 基金资助:
    Project supported by the National Basic Research Program of China (Grant No 2006CB605102) and the National Natural Science Foundation of China (Grant No 90306016).

Dislocation formation and twinning from the crack tip in Ni3Al: molecular dynamics simulations

Xie Hong-Xian(谢红献)a)†, Wang Chong-Yu(王崇愚)a)b)c), Yu Tao(于涛)a), and Du Jun-Ping(杜俊平)a)   

  1. a Central Iron and Steel Research Institute, Beijing 100081, China; b International Centre for Materials Physics, Chinese Academy of Sciences, Shenyang 110016, China; c Department of Physics, Tsinghua University, Beijing 100084, China
  • Received:2008-06-29 Revised:2008-08-20 Online:2009-01-20 Published:2009-01-20
  • Supported by:
    Project supported by the National Basic Research Program of China (Grant No 2006CB605102) and the National Natural Science Foundation of China (Grant No 90306016).

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摘要： The mechanism of low-temperature deformation in a fracture process of L12 Ni3Al is studied by molecular dynamic simulations. Owing to the unstable stacking energy, the [ 0\bar {1}1] superdislocation is dissociated into partial dislocations separated by a stacking fault. The simulation results show that when the crack speed is larger than a critical speed, the Shockley partial dislocations will break forth from both the crack tip and the vicinity of the crack tip; subsequently the super intrinsic stacking faults are formed in adjacent {111} planes, meanwhile the super extrinsic stacking faults and twinning also occur. Our simulation results suggest that at low temperatures the ductile fracture in L12 Ni3Al is accompanied by twinning, which is produced by super-intrinsic stacking faults formed in adjacent {111} planes.

关键词: molecular dynamic, crack, Shockley partial dislocation, stacking fault

Abstract: The mechanism of low-temperature deformation in a fracture process of L12 Ni3Al is studied by molecular dynamic simulations. Owing to the unstable stacking energy, the [ 0$\bar{1}$1] superdislocation is dissociated into partial dislocations separated by a stacking fault. The simulation results show that when the crack speed is larger than a critical speed, the Shockley partial dislocations will break forth from both the crack tip and the vicinity of the crack tip; subsequently the super intrinsic stacking faults are formed in adjacent {111} planes, meanwhile the super extrinsic stacking faults and twinning also occur. Our simulation results suggest that at low temperatures the ductile fracture in L12 Ni3Al is accompanied by twinning, which is produced by super-intrinsic stacking faults formed in adjacent {111} planes.

Key words: molecular dynamic, crack, Shockley partial dislocation, stacking fault

中图分类号:  (Grain and twin boundaries)

  • 61.72.Mm
61.72.Hh (Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)) 61.72.Nn (Stacking faults and other planar or extended defects) 62.20.M- (Structural failure of materials) 81.40.Np (Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure)