原子尺度计算机模拟
(西北工业大学 材料科学与工程学院， 西安 710072)
摘 要: 采用微观相场模型， 基于离散格点形式的微观扩散方程和非平衡自由能函数，编制了三元Ni75AlxV25-x合金的原子层面计算机模拟程序。模拟发现： 低铝含量Ni75AlxV25-x合金的θ相先于γ′相析出， 其沉淀机制为等成分有序化+失稳分解； γ′相在θ相的相界处非经典形核， 二者均先形成非化学计量比有序相， 之后向化学计量比有序相转变。
关键字: 早期沉淀； 原子尺度； 计算机模拟
of Ni75AlxV75-x alloys with lower Al concentration
（School of Materials Science and Technology,
Northwestern Polytechnical University, Xi′an 710072, China）
Abstract: With the microscopic phase-field model, the atomic-scale computer simulation programs of the ternary Ni-based alloys were worked out based on the microscopic diffusion equation and nonequilibrium free energy. The results show that for Ni75AlxV25-x alloy with lower Al composition, θ ordered phase precipitates earlier than γ′ ordered phase does by congruent ordering and spinodal decomposition mechanism, and thus produces a nonstoicheometric θ single ordered phase. Then, the nonstoicheometric γ′ phase precipitates by a non-classical nucleation and growth mechanism at the APBS of θ phases.
Key words: early precipitation process; atomic-scale; computer simulation
