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The temporal evolution feature of a microscopic phase field model is utilized to study the antisite defects of L1 2-Ni 3 Al;this is quite different from other physicist’ interests.There are mainly two points in brief.Firstly,antisite defects Ni Al and Al Ni ,which are caused by the deviation from the stoichiometric Ni 3 Al,coexist in the Ni 3 Al phase.The surplus Ni atom in the Ni-rich side is prone to substitute Al thus producing the antisite defect Ni Al that maintains the stability of the L1 2 structure.In other case,the surplus Al atom in the Al-rich side is accommodated by a Ni sublattice consequently giving rise to antisite defect Al Ni .The calculated equilibrium occupancy probability of Ni Al is much higher than that of Al Ni .This point is generally in line with other theoretical and experimental works.Additionally,both Ni Al and Al Ni have a strong negative correlation to time step during the disorder-order transformation.Since the initial value of Ni Al and Al Ni on each site of the matrix is right at the concentration that we set,we can observe the decrease process of Ni Al and Al Ni from the initial disordered high anti-structure state to their respective equilibrium state,i.e.to the result of the ordering process further coarsening.
The temporal evolution feature of a microscopic phase field model is utilized to study the antisite defects of L1 2-Ni 3 Al; this is quite different from other physicist ’interests. There are mainly two points in brief. Firstly, antisite defects of Ni Al and Al Ni, which are caused by the deviation from the stoichiometric Ni 3 Al, coexist in the Ni 3 Al phase. Surplus Ni atom in the Ni-rich side is prone to substitute Al for producing the antisite defect Ni Al that maintains the stability of the L1 2 structure.In other cases, the surplus Al atom in the Al-rich side is accommodated by a Ni sublattice cause giving rise to antisite defect Al Ni. The calculated equilibrium occupancy probability of Ni Al is much higher than that of Al Ni. This point is generally in line with other theoretical and experimental works. Additionally, both Ni Al and Al Ni have a strong negative correlation to time step during the disorder-order transformation. Since the initial value of Ni Al and Al Ni on each s ite of the matrix is right at the concentration that we set, we can observe the decrease process of Ni Al and Al Ni from the initial disordered high anti-structure state to their respective equilibrium state, ieto the result of the ordering process further coarsening .