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基于微观相场模型和微观弹性理论,对Ni75Al15Mn10合金γ′相沉淀过程以及原子占位进行了原子层面的计算机模拟。结果表明:合金在1273K进行时效,沉淀早期先析出L10结构,之后随着有序度的增加,逐渐转变为L12结构;原子的有序化早于成分簇聚,γ′相的沉淀机制为等成分有序化+失稳分解的混合机制;γ′有序相的体积分数比γ无序相小,且γ′和γ相的体积分数比值约为60%;Al原子主要占据β格点(γ′相顶角位置),αⅡ和αⅠ格点主要由Mn原子占据,且在αⅡ格点占位几率高于αⅠ格点,Mn原子主要占据Ni位,形成的γ′相为单一的(Ni,Mn)3Al相。
Based on the microscopic phase field model and the microscopic elasticity theory, the atomic layer computer simulation of γ ’phase precipitation and atom occupancy in Ni75Al15Mn10 alloy was carried out. The results show that the alloy is aged at 1273K and the L10 structure is precipitated in the early stage of precipitation, and then gradually changes to L12 structure as the degree of ordering increases. The ordering of atoms is earlier than that of the clusters, and the precipitation mechanism of γ ’ The order of composition and instability decomposition mechanism; γ ’ordered phase volume fraction γ less than the disorder phase, and γ’ and γ phase volume fraction ratio of about 60%; Al atoms occupy the main beta grid ( γ ’phase). The αⅡ and αⅠ lattice sites are mainly occupied by Mn atoms, and the occupancy of αⅡ lattice is higher than that of αⅠ lattice. The Mn atoms mainly occupy Ni sites and the γ’ phase is single (Ni , Mn) 3Al phase.