The microstructure stability of nanocomposites at elevated temperatures seems to be the most critical problem for their mechanical properties. The driving force for grain growth as well as for coarsening of the precipitate microstructure is extremely high, which causes a structure evolution at temperatures much lower than in standard structure materials. Several attempts have been made to stabilize the grain structure e.g. by decreasing the grain boundary energy by intensive segregation or to prohibit the precipitate coarsening by a significant narrowing of the precipitate size distribution or by a significant decrease of the concentration of an element, contained in the precipitate, in the matrix. The application of the Onsager’s thermodynamic extremal principle, formulated in discrete parameters, seems to be a handy tool for development of models for the microstructure evolution in complex nanosystems. The main goal of this project is to develop models by application of the thermodynamic e (en)
Vývoj modelu tlustého rozhraní pro efektivní popis segregace a tažení příměsí migrujícím rozhraním. Rozšíření stávajících modelů růstu zrn a hrubnutí precipitátů o efekty segregace a tažení příměsí. Aplikace rozšířených modelů na nanokompozity.
In agreement with the partial aim for 2012 the simulations of grain growth based on the model have been carried out. Using different data experimentally observed effects have been obtained: a mild retardation of the grain growth by segregation, spontaneous occurrence of abnormal grain growth in the system and nearly total blocking of the grain grovi/th. The paper is submitted in Acta Materialia. (en)
Ve shodě s dílčím cílem pro rok 2012 byly provedeny na základě vyvinutého modelu simulace růstu zrn v polykrystalu. Bylo dosaženo různých efektů potvrzených experimenty. Lze navodit situace, kdy je růst zrn bržděmn vlivem segregace jen mírně, kdy dochází ke spontánnímu abnormálnímu růstu zrn v systému i kdy je růst zrn prakticky zablokován. Článek je zaslán k publikaci do Acta ÍVIaterialia. (cs)