Dmytrenko T. Formation of surface layers structure of plain carbon steels during the laser alloying by titanium diborid.

Thesis deals with the study of structure formation processes in the surface layers of plain carbon steels during the laser alloying depending on treatment regimes and structure phase state of matrix material. New results give the opportunity to establish regularities of new alloy formation depending on the content of carbon during laser alloying by boron-based compound.The mechanism of fusion crystallization during laser alloying by titanium diborid under condition of ultraspeed heating and cooling rates is proposed. Correlation between type of formed phases and content of carbon in base material is established. Processes of the concentration distribution formation depending on the technological parameters of laser treatment are studied. The influence of alloying elements on the type of formed structure and physics and mechanical properties of the laser alloying areas is explored. The results of the temperature field distribution simulation in a laser beam area can be applied for forecast of conditionswhich are necessary for formation of certain structure of surface alloyed layer, for development of surface layers strengthening technologies by laser alloying