THE “4SIMPLEX” PLARFORM FOR PREDICTING PHASE EQUILIBRIA AND DECOMPOSITION KINETICS OF SOLID SOLUTIONS IN MULTICOMPONENT SYSTEMS (USING THE Co-Ti-Ta-Re SYSTEM AS AN EXAMPLE)тезисы доклада
Аннотация:Predicting of phase equilibria in quaternary and higher-dimensional systems is an important task for the development of advanced materials. Traditional approaches to constructing of multicomponent systems isothermal sections using graphs method by hand are extremely labor-intensive and error-prone. Moreover, the use of only isothermal sections doesnot allow tracking the kinetics of processes such as recrystallization, aging, and tempering, ortracking the evolution of metastable intermediate particles. The integrated computing platform “4simplex”, developed in the course of this work,significantly accelerates and automates the key stages of the analysis of multicomponent systemsand the processing of experimental data. Specialized software has been developed in the Python for constructing and visualizing isothermal sections of four-component systems in the form oftetrahedrons. The platform has been successfully tested on experimental data obtained in the analysis of alloys of the four-component Co-Ti-Ta-Re system. The alloys were prepared in an electric arc furnace in an argon atmosphere, heat treatment was carried out in evacuated quartz ampoules inelectric resistance furnaces. The methods of scanning electron microscopy, EDX, X-ray phaseanalysis, transmission electron microscopy and electron diffraction were used in this work. In“4simplex”, the surface of the fcc cobalt solid solution (γCo phase) at 1375 and 1200 K wasmathematically described and constructed, and concentration ranges suitable for obtainingnanoparticles of the strengthening phase γ'-Co3Ti (prototype Cu₃Au) and the metastable phase ε'-Co3Ta (prototype Mg₃Cd) were determined. The tools used in the platform allowed mapping the surfaces of the γCo phase and the adjacent regions of two-phase equilibria at the specified temperatures. The purpose of mapping was to obtain data on the regions of existence of brittle Laves phases, as well as the volume fractions of the γ'-Co3(Ti,Ta) and ε'- Co3(Ti,Ta) phases released during aging. A number of temperature-time series were constructed to visualize the kinetics of the release of the γ'-Co3(Ti,Ta) and ε'- Co3(Ti,Ta) phases during aging, as well as the martensitic transition of γ'-Co3(Ti,Ta) to ε'- Co3(Ti,Ta) during tempering. The platform “4simplex” has high potential for accelerated design of new multicomponent alloys with a given microstructure and a given set of properties.
