Phase equilibria data of the Al-Nb-V system are important for the design of innovative, low-density, Al-containing refractory high-entropy alloys. The scholarship candidate, MSc. Júlio César Pereira dos Santos, started the studies in this system in his master work determining the isothermal section at 1200 °C and performing a preliminary thermodynamic modelling of the system using microstructural characterization results of heat-treated samples. At that time, microanalysis results showed compositional deviations from expected phase stoichiometries which could not be explained by solid solution formation. Therefore, the need to continue investigating the Al-Nb-V system using more advanced microstructural analysis techniques has become clear. The preliminary character of the thermodynamic modelling is due to the lack of information in terms of other isothermal sections as well as liquidus projection for this system. In his PhD, the candidate is continuing the investigation phase equilibria involving solid phases using more precise equipments for microanalyses of heat-treated samples as well as carrying out the investigation of the liquidus projection of the Al-Nb-V system. For the latter, he produced and analysed 42 as-cast alloys and already has a preliminary proposal for the liquidus projection. However, its Nb-rich region is still not well determined and more experiments are needed. For some of these analyses, high-resolution micrographs at high magnifications are necessary due to the small dimensions of the phases formed during solidification. In the host institution, there are adequate microscopes to do these analyses. All the experimental results will be very important to feed the optimization procedure during the modelling of the Al-Nb-V system, which is an important part of his PhD project. Eventually, some critical samples will be produced according to the need indicated by the modelling process. During the candidate research internship at the host institution, he will perform both the experimental and modelling research in partnership with experienced researchers in the field. At the end of the project, the objective is to propose a self-consistent thermodynamic modelling for the Al-Nb-V system.
News published in Agência FAPESP Newsletter about the scholarship: