On the transition from diffusion-limited to kinetic-limited regimes of alloy solidification

作者：Sobolev S L^*

来源：Acta Materialia, 2013, 61(20): 7881-7888.

DOI：10.1016/j.actamat.2013.09.027

• Rapid solidification
• Analytical modeling
• Non-equilibrium
• Diffusionless solidification

An abrupt transition from diffusion-limited solidification to diffusionless, kinetic-limited solidification with complete solute trapping is explained as a critical phenomenon which arises due to local non-equilibrium diffusion effects in the bulk liquid. The transition occurs when the interface velocity V passes through the critical point V = V-D, where V = V-D is the bulk liquid diffusive velocity. Analytical expressions are developed for velocity-temperature and velocity-undercooling functions, using local non-equilibrium partition coefficient based on the Jackson et al. kinetic model and the local non-equilibrium diffusion model of Sobolev. The calculated functions demonstrate a sharp break in the velocity-undercooling and velocity-temperature relationships at the critical point V = V-D. At this point the local non-equilibrium solidus and liquidus lines coincide with the T-0 temperature. The relationship to pertinent experiments and the influence of the local non-equilibrium diffusion effects on grain refinement and disorder trapping phenomena are discussed.

• 出版日期2013-12