L1_2相间有序畴界成分的微观相场研究

Microscopic Phase-Field Study on the Compositions of Ordered Domain Interfaces Formed between L1_2 Phases in Ni_(75)Al_xV_(25-x) Alloys

利用微观相场模型研究了有序畴界结构、合金成分和弹性应变能对Ni75AlxV25-x合金中L12-Ni3Al相间有序畴界成分的影响规律。结果表明:L12相间形成的3种有序畴界中,在(100)//(200)·[001]处,Ni的贫化程度最小,Al的贫化程度最大,V的偏聚程度最大;在(200)//(200)处,Ni的贫化程度最大,Al的贫化程度最小,V的偏聚程度最小。随着合金中Al浓度的增加,3种有序畴界处Ni的浓度降低,Al的浓度升高,V的浓度降低。弹性应变能使得L12相间3种有序畴界处Ni和Al的浓度升高,V浓度降低。但弹性应变能对(200)//(200)·[001]和(100)//(200)·[001]成分的影响较大,对(200)//(200)成分的影响则相对较小。

Microscopic phase-field model was used to study the effect of atomic structure of interfaces, composition of alloys and elastic strain energy on the compositions of ordered domain interfaces formed between L12-Ni3Al phases in Ni75AlxV25-x alloys. The results demonstrate that the depletion degree of Ni is the lowest, and the depletion degree of Al and the segregation degree of V are the highest at the interface （100）//（200）· [001]; the depletion degree of Ni is the highest, and the depletion degree of Al and the segregation degree of V are the lowest at the interface （200）//（200） among the three kinds of interfaces formed between L12-Ni3Al phases. With the Al concentration of alloys increasing, the concentration of Al increases while the concentrations of Ni and V decrease at the ordered domain boundaries formed between L12-Ni3Al phases. When the elastic strain energy is considered during the simulation, the concentrations of Ni and Al increase while the concentration of V decrease at the three kinds of ordered domain interfaces. The effect of elastic strain energy on the composition of （200）//（200）· [001] and （100）//（200）· [001] is much more remarkable than on that of （200）//（200）.