Shport'ko G. Regularities of structure formation of eutectic silumin with increased level of mechanic properties after controlled conversion from liquid state to solid one

Thesis is directed to increasing of silumins mechanic level of properties. In research the analysis of foreign and domestic literature has been performed on the subject of transformations in the metallic melts of eutectic silumins (theory of metallurgical heredity), of high-speed solidification of this melts, of creation of metastable intermediate phases in Al-Si system, of influence of superheat temperature and cooling rate on structural characteristics and mechanical properties of the alloys after their solidification. The regularities of structure formation of eutectic silumin in cast state in dependence of heating temperature of the melt and its cooling rate have been studied. The structure of liquid eutectic silumin has been studied and investigation of influence of curing temperature of the melt (thermo-temporary treatment) on parameters of short-range order of the clusters has been carried out. The regularities of solid-phase transformations of rapid-hardening fine films, which had been obtainedfrom the melts with various heating over liquidus line by chill block melt spinning method have been studied. Investigation of influence of thermo-temporary treatment of melt on structure and mechanicals properties has been carried out. The prompts regarding application of thermo-temporary treatment of the melt before its solidification in the production of goods of AK12 (АЛ2) has been proposed on the grounds of the experimental results, which showed that conditions of heating effected essentially on state of liquid metal, on process of its solidification, on the structure and properties of solidified metal. Key words: eutectic alloy, melt structure, clusters, high-speed solidification, chill block melt spinning, fine metallic films, metastable intermediate phases, mechanical properties.