The influence of interface kinetics on the morphological stability of directional solidification of metls

The linear theory of stability was applied to the study of the marginal stability of stationary directional solidification in binary systems with respect to the kinetic material parameter Γ characterizing the rate of phase transformation. The theory is not restricted to dilute solutions. It was determined that for any value of Γ there exists a critical value ω crit of the frequency of front perturbation and undercooling on the solidification front ΔT crit such that for undercooling ΔT ΔT crit the solidification process is stable. ω crit and ΔT crit depend on Γ. At lower values of Γ the solidification process is more stable. ω crit increases with increase of Γ. In this paper the quantitative dependences ΔT crit ( Γ ) and ω crit ( Γ ) are proposed for a particular type of materials. The transport properties of materials do not change these quantitative results. Stability analysis is general, but our particular calculations are limited to regular solutions.