Multi-component and multi-phase alloys form the foundation of advanced materials design, Their complex microstructure evolution provides materials engineers with a nearly inexhaustible variety of solutions to enhance material properties.
However, this large design space also comes with huge challenges. To exploit the potential of multi-component alloy design in the best and most responsible way, a profound understanding of how compositional variations and heat treatments affect microstructure evolution in these alloys is necessary. Simulations play a key role in obtaining these insights.
At the Microstructure Simulation Lab Leuven we have developed our own quantitative and thermodynamically consistent phase-field approaches for multi-phase and multi-component systems. We have extensive experience in using the phase-field method coupled with CALPHAD Gibbs energy and diffusion mobility models in studies of phase transformations, coarsening and interdiffusion phenomena in multi-component systems.
High-entropy alloys (HEAs) and multi-principle-element alloys (MPEAs) represent an innovative class of materials attracting large interest. Certain HEAs have shown to exhibit unique properties, such as, the magnetocaloric effect, high strength and excellent ductility--difficult to achieve in traditional alloys. Moreover, unlike conventional alloys, which are based on a single major element, HEAs/MPEAs contain multiple principal components in nearly-equal atomic ratios, opening a vast, unexplored design space.
For HEAs/MPEAs, we have developed a new simulation framework that efficiently integrates CALPHAD Gibbs energy and diffusion mobility models into a multi-component, multi-phase phase-field model using data-driven techniques. The framework has been applied to study microstructural processes relevant to AlCrFeNi based alloys, an important family of HEAs.
Soldering is a crucial process in microelectronics to obtain a reliable electrical and mechanical connection between components and circuit boards. With the trend toward miniaturization, advanced soldering techniques, such as reflow and wave soldering, are continuously further optimized for high-density and precision assembly. Furthermore, selecting new solder materials is needed for improving joint reliability, thermal performance, and long-term durability in electronic devices.
The phase-field method is ideal for simulating the interdiffusion and IMC growth and morphology at solder--bump interfaces, providing important insights for the development of new solder alloys and techniques.
Study of the effect of Sn grain boundaries on IMC morphology in solid state interdiffusion soldering (2019)
Phase-field study of IMC growth in Sn-Cu/Cu solder joints including elastoplastic effects (2020)
Formation of compounds and Kirkendall vacancy in the Cu-Sn system (2014)
Phase-field analysis of a ternary two-phase diffusion couple with multiple analytical solutions (2011)
The study of slag crystallization, dissolution of oxides in metallurgical slags and the behavior of metallic
The study of crystallization, dissolution and wetting phenomena in metallurgical slags plays a key role in the optimization of metal refining and recycling processes. The fraction, shape and distribution of solide phases influences slag viscosity and rheological behavior, while the wetting and dissolution behavior of metallic droplets and particles impacts metal recovery efficiency.
A phase-field model for isothermal crystallization of oxide melts (2011)
Phase-field simulation and analytical modelling of CaSiO3 growth in CaO-Al2O3-SiO2 melts (2018)
Towards more realistic simulations of microstructural evolution in oxidic systems (2022)
Crystallization of CaO.SiO2 in a CaO-Al2O3-SiO2 Melt: Computer simulations and in-situ experiments (2011)
In collaboaration with Inge Bellemans and Kim Verbeken, Ghen University, we studied the reactive wetting of metallic droplets to spinel solid particles in pyrometallurgical slags.
Multi-phase phase-field models are the most suitable models for studying coarsening behavior in multi-phase microstructures, especially when three or more elements and/or phases are involved.
Microstructure evolution occurs over a wide range of length scales (from nanometers to millimeters), often at scales several orders of magnitude larger than the width of interfaces and grain boundaries (typically 0.1-0.5 nm). For numerical efficiency, the width of the diffuse interfaces in phase-field models must be increased artificially by several orders of magnitude when simulating on experimentally relevant length scales. An important challenge in phase-field modeling is developing models with scalable diffuse interface width that preserve the accurate representation of boundary energy and mobility--known as thin-interface models--, for efficient simulations on experimental lengths scales.
Microstructure simulation of grain growth in Cu through silicon vias using phase-field modeling (2015)
(c) 2025, Nele Moelans. Last update Aug. 2025.