EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Understand and control the growth of intermetallic phases between dissimilar alloys is the key factor in optimizing the bond strength of hybrids produced by compound casting. Being able to predict the final state of a cast part is the driving force to the development of mathematical models and numerical methods that can represent the phenomena and be applied to assist the interpretation of processes parameters effects over the casting quality. Analytical models have long been used to describe the final cast state, such as well-known models to predict porosity and the fraction of phases in cast irons. These models have provided the link between what happens on the microscopic level with the macroscopic scale, as in many situations, exact simulations at the microscopic level are still unpractical. In this work, we present an analytical model for predicting the thickness of intermetallic layers at the interface contact of aluminum-brass hybrids produced by compound casting. To assist the construction of the model, we apply solid-liquid diffusion couple experiments to isolate the temperature and time effects at the interface and obtain the necessary parameters of our model, such as growth rates and activation energies. The model extension to non-isothermal conditions is constructed and validated, which resembles the compound casting processes. In this matter, we evaluate the process parameters' influence over the interface by including the developed model as an interfacial condition in our current compound casting model. Now, the model is limited to the temperature range in which no intermetallic phases precipitate within the ones formed at higher temperatures as we only predict the growth of the layers and not their shrinkage. To overcome this limitation, as further steps, we seek to include in the model the effects of thermodynamic quantities to assist the phase transformations evolutions during the diffusion-reaction process.