Analytical solution of a binary melt solidication model in the presence of a quasi-equilibrium mushy region for the case of the non-linear phase diagram.

The process of directional crystallization with a quasi-equilibrium mushy region is considered in the steady-state conditions with allowance for the non-linear phase diagram. A complete analytical solution of model equations is found in a parametric form by introducing a new variable - the solid phase fraction in the mushy layer. The temperature and solute concentration, as well as the solid fraction in the mushy layer, its boundaries, and the crystallization velocity, are determined analytically. It is shown that a non-linear phase diagram substantially influences the behaviour of solutions obtained.