Abstract The diffusion process in multicomponent alloys has a significant influence on the evolution of the microstructure. The Calphad approach is a powerful method for describing the equilibrium state as well as the kinetics of non-equilibrium systems via the Gibbs energy. In this work, the principles of multicomponent diffusion theory are considered intensively, and an equation for the fluxes in the case of substitutional-interstitial diffusion is given for implementation. Additionally, the calculation of mobility matrices and thermodynamic factors is addressed. As an application case, substitutional diffusion is implemented in OpenCalphad and is used for calculating the growth rate for spherical precipitates from a supersaturated aluminum matrix. The growth rate has been integrated into the Kampmann–Wagner numerical model, which describes nucleation, growth, and coarsening for spherical precipitates. A AlMgZnCu alloy is considered, which has great significance in the field of materials processing.

中文翻译：

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OpenCalphad 中扩散驱动的微观结构演化

摘要 多元合金中的扩散过程对显微组织的演变有重要影响。Calphad 方法是一种通过 Gibbs 能量描述平衡状态以及非平衡系统动力学的强大方法。在这项工作中，深入考虑了多组分扩散理论的原理，并给出了替代填隙扩散情况下的通量方程以供实施。此外，还讨论了迁移率矩阵和热力学因素的计算。作为一个应用案例，替代扩散在 OpenCalphad 中实现，用于计算来自过饱和铝基体的球形沉淀物的生长速率。增长率已被整合到 Kampmann-Wagner 数值模型中，它描述了球形沉淀物的成核、生长和粗化。考虑了AlMgZnCu合金，其在材料加工领域具有重要意义。