Phae fielde models of solifidct in binary alloys:caplillaryiten　 solute trapping ekffects

摘要

Phase fileld models of soluion in alloys with order parameter, concentrationand temeprature as field variables are reoconsidred. The free energy in these models includes the gradetion contributions dur to the pahde field and the concetnration field. Equilibrium properites of these models, such as the pahse diagrams for curved interfaces, spatial structure of the pahse and the compsotin fields and he dependence of surface tension on the concentrtion of impurities are analyzed. Solute trapping in planar solidification is studied for severla groth regimes, accounting for a substraintial difference in the diffustivites of solid and liquid. Owing to this difference there existts partial soloute trapping at certain osolidification speeds.