The Formation and Dynamic Evolution of Antiphase Domain Boundary in FeAl Alloy: Computational Simulation in Atomic Scale

The main objective of the present work is to build a model and analyze the dynamic evolution process of antiphase domain boundary (APDB) in FeAl alloy. The formation, evolution of APDB, long range order (LRO), the crystal structure transition, impact of temperature on LRO, are investigated. Comparisons with experiments proves that the model is competent for the dynamic investigation of APDB in microscopic scale and able to predict different boundary-types and their corresponding atoms distribution. The dynamic process shows that the initial distribution of premier micro domains determine the morphology of APDB. The morphological evolution of APDB significantly affects the quantity of APDB. The in situ observation shows that the crystal structure of a micro domain is altered by the APDB movement. The calculated LRO revealed that the atoms in Al-sublattice mainly contribute to the low order degree of FeAl at different temperatures.

本研究的核心目标为构建模型，并分析铁铝（FeAl）合金中反相畴界（antiphase domain boundary, APDB）的动态演化过程。本研究围绕反相畴界的形成与演化、长程有序（long range order, LRO）特性、晶体结构转变以及温度对长程有序的影响展开了系统探究。通过与实验结果的对比验证，本模型可胜任微观尺度下反相畴界的动态研究，并能够预测不同类型的畴界及其对应的原子分布。动态演化分析显示，初始首要微畴的分布格局决定了反相畴界的形貌特征；反相畴界的形貌演化对其自身的数量具有显著影响。原位观测结果表明，反相畴界的运动能够改变微畴的晶体结构。计算得到的长程有序参数显示，在不同温度条件下，铝亚晶格中的原子是导致铁铝合金有序度偏低的主要因素。