Analysis of the structure and viscosity of iron melts containing titanium at various concentration

Abstract

This study aims to investigate the correlation between viscosity and liquid structure in Fe-4.5 wt%C-xTi melts. As the temperature decreases, Free-Fe and A-Fe species undergo a transformation into B-Fe, resulting in a significant reduction in free volume. This leads to the aggregation and growth of existing clusters as well as the formation of new clusters, thereby increasing both the number and average volume of atomic clusters. Consequently, the viscosity of the melt experiences a substantial increase as the temperature decreases. In the high-temperature liquid phase region, an elevated titanium content enhances the abundance of titanium-centered clusters within the melt, promoting the stable growth of atomic clusters. Additionally, the increased presence of titanium facilitates the binding of a greater number of carbon atoms and enhances the occupation of free space by iron atoms. As a combined effect, the viscosity of the molten iron rises with an increase in titanium content. At temperatures below the liquidus temperature, a higher titanium content decreases the precipitation temperature of graphite. Consequently, melts with a greater titanium content exhibit a pronounced increase in viscosity at a lower temperature threshold. The primary factor influencing viscosity is the mass fraction of graphite precipitation, and the impact of titanium content diminishes as the titanium content increases.