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Full-Text Articles in Engineering Physics
Diffusion-Stress Coupling In Liquid Phase During Rapid Solidification Of Binary Mixtures, Sergey Sobolev
Diffusion-Stress Coupling In Liquid Phase During Rapid Solidification Of Binary Mixtures, Sergey Sobolev
Sergey Sobolev
An analytical model has been developed to describe the diffusion-viscous stress coupling in the liquid phase during rapid solidification of binary mixtures. The model starts with a set of evolution equations for diffusion flux and viscous pressure tensor, based on extended irreversible thermodynamics. It has been demonstrated that the diffusion-stress coupling leads to non-Fickian diffusion effects in the liquid phase. With only diffusive dynamics, the model results in the nonlocal diffusion equations of parabolic type, which imply the transition to complete solute trapping only asymptotically at an infinite interface velocity. With the wavelike dynamics, the model leads to the nonlocal …
On The Transition From Diffusion-Limited To Kinetic-Limited Regimes Of Alloy Solidification, Sergey Sobolev
On The Transition From Diffusion-Limited To Kinetic-Limited Regimes Of Alloy Solidification, Sergey Sobolev
Sergey Sobolev
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 velocityVpasses through the critical pointV=VD, where V=VDis the bulk liquid diffusive velocity. Analytical expressions are developed for velocity–temperature and velocity–undercooling functions, using local non-equilibrium partition coeffi-cient based on the Jackson et al. kinetic model and the local non-equilibrium diffusion model of Sobolev. The calculated functions dem-onstrate a sharp break in the velocity–undercooling and velocity–temperature relationships at the critical pointV=VD. At this point …