Interfacial reaction and diffusion kinetics in solid-liquid couples of the Al – Cu – Zn system: experiments and multiscale simulations

将具有不同机械、化学和物理性能的材料组合在一个单一组件中的能力，导致了具有改进性能的混合组件的发展，以满足技术和工业的进步。复合铸造工艺在这里被强调，因为它是一种生产半成品混合材料的有效方法。在此过程中，高温促进初始产物在接触界面处的扩散和反应，形成脆性金属间层。从技术的角度来看，工程师试图了解金属间相的发展如何影响其最终组件的性能，而冶金学家和材料科学家则提供有关合金化学的基本信息，这些信息负责混合部件的最终粘合质量。因此，了解和控制这些金属间相的形成和生长是优化新开发的杂化元件结合强度的关键因素。在这个问题上，能够可靠地预测最终的金属间层厚度并避免一系列的反复试验是至关重要的。目前，对于铝合金和黄铜的复合铸造，由于主要元素Al、Cu和Zn的复杂扩散行为，阻碍了金属间层厚度的数值预测。本项目的目的是发展一种连续的多尺度方法，其中分子动力学（MD）模拟有望提供扩散率数据，这些数据需要包含在描述复合铸造过程中固液扩散过程的宏观模型方程中。这种多尺度方法将允许预测多组分-多相复合Al-Cu-Zn体系中的金属间层厚度。为了实现我们的目标，基本的扩散实验是验证MD模拟结果的必要条件。为了研究界面形成机制和验证金属间层厚度的结果，将进行实验室规模的固液扩散实验。

The ability of combining materials with different mechanical, chemical and physical properties in a single component gives rise to the development of hybrid components with improved properties that meet technological and industrial advances. The compound casting process is highlighted here, as it is an efficient method to produce semi-finished hybrids. During the process, the high temperatures promote diffusion and reaction of the starting products at the contact interface and brittle intermetallic layers form. From a technological point of view, engineers seek to understand how the development of intermetallic phases affects the performance of their final component while metallurgists and material scientists contribute the essential information on alloy chemistry responsible for the final bond quality of the hybrid parts. Understanding and controlling the formation and growth of these intermetallic phases is, therefore, the key factor in optimizing the bond strength of newly developed hybrid components. In this matter, being able to reliably predict the final intermetallic layer thickness and to avoid a series of trial-and-error experiments is fundamental. At the moment, for compound casting of aluminium alloys and brass, the numerical prediction of the intermetallic layer thicknesses was hindered due the complex diffusion behavior of the main elements Al, Cu and Zn. The aim of the present project is the development of a sequential multiscale approach, where molecular dynamics (MD) simulation is expected to provide the diffusivity data that are needed to be included into the macro-model equations that describe the solid-liquid diffusion process during compound casting. That multiscale approach will allow the prediction of intermetallic layers thicknesses in the multicomponent-multiphase complex Al-Cu-Zn system. To achieve our goal, fundamental diffusion experiments are essential to validate the MD simulation results. Laboratory scale size solid-liquid diffusion experiments will be performed in order to investigate the interface formation mechanism and to validate the results for the intermetallic layers thickness.