Formation of cast structure in relation to temperature and time parameters of melting and crystallization

Abstract

The influence of the melt overheating temperature over the equilibrium liquidus and the cooling rate of it during crystallization, the effect of the temperature of the isothermal processing of the melt in the pre-crystallization period and in the temperature interval of crystallization under conditions of normal and high-speed thermal selection on the formation processes of cast structure was researched by methods of physical modeling using transparent model material (camphene). It has been established that the formation of a coarse-grained structure with significant overheating of the melt can be eliminated by its rapid cooling during crystallization, which ensures the formation of a fine-grained structure with a high dispersion of the dendritic structure. It is shown that in a narrow temperature range of underliquidus area during the isothermal processing solid phase crystals form and accumulate without substantially increasing their size, providing the formation of a dispersed cast structure with subsequent rapid melt cooling.

Keywords

• physical modeling
• liquidus
• superheat temperature
• crystallization
• structure formation
• isothermal treatment.