Matviychuk Y. Physical principles of forming of high strength conditions in beta titanium alloys by rapid heat treatment methods

The thesis is dedicated to development of physical principles of forming of high strength conditions in metastable beta titanium alloys at rapid heat treatment by the investigation of phase and structural transformations taking place at continuous heating. The dependence of parameters of the alpha+beta-betaтаphase transformation and, correspondingly, parameters of the grain structure of the high temperature beta phase upon morphology and degree of imperfection of the initial beta alloys structure have been studied. Deformability of beta alloys and its relation with initial sub-grain structure of metastable beta phase have been studied. The regularities of the grain structure formation during recrystallization under rapid heat treatment of the deformed metastable beta phase have been studied. The kinetics of the metastable beta phase decomposition and influence of the heating rate onto decomposition mechanism have been studied. It was shown that beta phase decomposition mechanism depends on heating ratethat defines morphology of alpha phase precipitates. Results obtained allowed to optimize heat treatment regimes to obtain significantly better strength/ductility balance as compared to conventional treatments for all studied alloys.