The molecular dynamics （MD） simulation and the modified analytical embedded-atom method （MAEAM） were used to study the influence of a He atom on the movement of the（a/2）？110？{111} edge dislocation in Ni. First...The molecular dynamics （MD） simulation and the modified analytical embedded-atom method （MAEAM） were used to study the influence of a He atom on the movement of the（a/2）？110？{111} edge dislocation in Ni. First, the calculated Burgers vector distribution shows that the equilibrium dissociation distance （Ded） and the stacking fault energy （Esf） between two partial edge dislocations are about 25.95 ？ and 108 mJ/m2, respectively. Then, the obtained formation energies （Ef） of a He atom at some different sites demonstrate that the He atom is attracted and repelled in the tension and compression regions, respectively. And the He？dislocation interaction reveals that an interstitial He atom plays a more significant role in the dislocation movement than a substitutional He atom. Finally, it is found that the movement of an interstitial He atom is apparent as the first partial dislocation bypasses and the edge dislocation offers fast-diffusion path for the migration of a He atom.展开更多
The influence of ordered structure on the dislocation configuration,structure of anti-phase domain boundary,partial dislocation slips,etc.are analyzed in the background of promoting the plasticity of iron based ordere...The influence of ordered structure on the dislocation configuration,structure of anti-phase domain boundary,partial dislocation slips,etc.are analyzed in the background of promoting the plasticity of iron based ordered solid solutions with second-order phase transformation.The principles of deformation softening and annealing hardening in ordered solid solutions are discussed because of deformation induced structure disordering.It is concluded that the independent slip ability of the partial dislocations and the corresponding low temperature plasticity of ordered solid solutions could be promoted obviously by proper alloying effects,which reduces the anti-phase domain boundary energy,or by maintaining the disordering state into the low temperature range.The similar principles could be also used to modify the low temperature plasticity of other metal based ordered solid solutions.展开更多
基金Project(ZL1405)supported by the Talent Project of Lingnan Normal University,China
文摘The molecular dynamics （MD） simulation and the modified analytical embedded-atom method （MAEAM） were used to study the influence of a He atom on the movement of the（a/2）？110？{111} edge dislocation in Ni. First, the calculated Burgers vector distribution shows that the equilibrium dissociation distance （Ded） and the stacking fault energy （Esf） between two partial edge dislocations are about 25.95 ？ and 108 mJ/m2, respectively. Then, the obtained formation energies （Ef） of a He atom at some different sites demonstrate that the He atom is attracted and repelled in the tension and compression regions, respectively. And the He？dislocation interaction reveals that an interstitial He atom plays a more significant role in the dislocation movement than a substitutional He atom. Finally, it is found that the movement of an interstitial He atom is apparent as the first partial dislocation bypasses and the edge dislocation offers fast-diffusion path for the migration of a He atom.
基金supported by the Independent Research Project of the State Key Laboratory for Advanced Metals and Materials (Grant No. 2010z-12)
文摘The influence of ordered structure on the dislocation configuration,structure of anti-phase domain boundary,partial dislocation slips,etc.are analyzed in the background of promoting the plasticity of iron based ordered solid solutions with second-order phase transformation.The principles of deformation softening and annealing hardening in ordered solid solutions are discussed because of deformation induced structure disordering.It is concluded that the independent slip ability of the partial dislocations and the corresponding low temperature plasticity of ordered solid solutions could be promoted obviously by proper alloying effects,which reduces the anti-phase domain boundary energy,or by maintaining the disordering state into the low temperature range.The similar principles could be also used to modify the low temperature plasticity of other metal based ordered solid solutions.
