双粒子模型的基础是描述原子之间相互作用势为EAM(embedded atom method)势的Monte Carlo模拟.模型建议:在Ni3Al晶界弛豫时,微量元素原子既被看作为偏析子又被看作为诱发子.作为偏析子它在晶界偏析(或富集),作为诱发子它诱发Ni原子在晶界偏析(或富集).可见本模型能解析共偏析(或共富集)现象.根据正(或诱发子)效应与负(或偏析子)效应的联合影响,模型解释了Ni在Ni3Al晶界最明显富集现象.
The Monte Carlo simulation with the energetics described by the embedded atom method has been employed to mainly study physical behaviors of boron atoms during relaxation of the Ni3Al-x at.% B grain boundary.During relaxation of impure Ni3Al grain boundaries,we suggest that for different types of impure atoms(Mg,B,Cr and Zr atoms etc.),as the segregating species,they have the different behaviors,but as the inducing species,they have the same behaviors,i.e.they all induce Ni atoms to substitute Al atoms.Calculations show that at the equilibrium.when x(the B bulk concentration) increases from 0.1 to 0.9,the peak concentration of B increases,correspondently,the peak concentration of Ni maximizes but the valley concentration of Al minimizes,at x=0.5,The calculations also show the approximate saturation of Ni at the grain boundary at x=0.5.
