MATHEMATICAL MODELING OF TITANIUM INGOT SOLIDIFICATION PROCESSES

摘要

Modeling and simulation of ingot solidification of Ti alloys requires complex multi-scale computations, from computational fluid dynamics (CFD) macroscopic modeling through mesoscopic to microscopic modeling, as well as strategies to link various length scales emerged in modeling of microstructural evolution. Solidification modeling of plasma arc melting (PAM) ingot processes is presented. Two aspects were considered to improve the quality of the cast ingots: (ⅰ) optimal melt rate (or casting speed) and (ⅱ) solidification maps of Ti-17 and Ti-6-4 alloys. Electromagnetic stirring (EMS) technique, an alternative solution for controlling the solidification structure formation during the PAM process, will also be covered. The EMS modeling approach is based on the numerical solution of Maxwell's equations, fluid flow and heat transfer equations, and mesoscopic modeling of the grain structure.