Transient rapid solidification of dilute binary alloys is addressed in the frame of the continuous growth model, accounting for solute trapping effects. We consider the planar isothermal growth from a melt of some uniform initial composition. The initial solute concentration in the melt is assumed to be below its equilibrium value. An approximate solution of this problem is developed using the mass balance integral method with the boundary-layer-type profiles for solute concentration. This solution is validated by the numerical solution of the original moving boundary problem. The influence of solute trapping effects on the main evolution characteristics of the process is discussed. The transient regime and the long-time asymptotic states are investigated. The physics of the process is clarified using the Baker-Cahn diagrams for a solute concentration at the interface. © 1996 The American Physical Society.

• Received 13 December 1995

DOI:https://doi.org/10.1103/PhysRevE.54.588