微观相场法计算Fe含量对NiAlFe三元合金中反位缺陷的影响

Microscopic Phase-Field Calculations on the Effect of Fe Content on Antisite Defects in NiAlFe Ternary Alloys

摘要:

采用三元微观相场模型，对铝含量大于25% (原子分数, 下同)与镍含量大于75% (原子分数, 下同)的NiAlFe三元合金中反位缺陷NiAl、AlNi随Fe含量变化的规律进行模拟计算，其中NiAl(AlNi)表示Ni(Al)原子占据Al(Ni)格点产生的反位缺陷。结果表明：在一定温度范围内，随着Fe含量的增大，铝含量大于25%的NiAlFe合金中AlNi浓度明显上升，NiAl浓度略有上升，但小于AlNi浓度，相反在镍含量大于75%的NiAlFe合金中NiAl浓度明显上升且远大于AlNi浓度；同一温度下比较铝含量大于25%与镍含量大于75%的NiAlFe合金中反位缺陷受Fe含量影响的程度差异，发现前者的AlNi浓度比后者受Fe含量影响大，而后者的NiAl浓度比前者受Fe含量影响大。此外，反位缺陷NiAl和AlNi浓度随时间的演化规律均是逐渐由初始值降低至平衡值；温度升高促使反位缺陷演化变缓慢以及平衡时浓度增大

Abstract:

Using the ternary microscopic phase-field model, the effect of Fe content on antisite defects NiAl and AlNi in two types of NiAlFe ternary alloys were simulated and calculated; one type is the NiAlFe alloy with Al content larger than 25%, and the other type is the NiAlFe alloy with Ni content larger than 75%. NiAl (AlNi) stands for the antisite defect which is caused by Ni(Al) atoms occupying Al(Ni) sites. The results show that, in a certain temperature range, with more Fe added, in NiAlFe alloys with Al content larger than 25% the AlNi concentration increases obviously, while the NiAl concentration increases slightly whose values are smaller than AlNi concentration; on the contrary, in NiAlFe alloys with Ni content larger than 75% the NiAl concentration increases obviously and its values are larger than AlNi concentration; at the same temperature, we made a comparison between the NiAlFe alloys with Al content larger than 25% and the NiAlFe alloys with Ni content larger than 75% to study the influence of Fe content on antisite defects in these two types of alloys, and found that AlNi concentration in the former alloys is more easier to be affected by Fe content than in the latter alloys, while NiAl concentration in the latter alloys is more easier to be affected by Fe content than in the former alloys. Besides, the concentrations of NiAl and AlNi change with timesteps gradually from an initial value to the equilibrium value; elevating the temperature causes the evolution process of antisite defects to turn slower and the equilibrium values become lager