EFFECT OF STRESS ACTING UPON THE SOLID NETWORK IN THE 2-PHASE ZONE DURING SOLIDIFICATION

Having taken the solid network movement in the two-phase zone into con sideration, this paper develops the original local solute redistributi on equation. The additional term divV'(s) in the new equation is depen dent on the history of an effective stress sigma' acting upon the soli d network. The solidifying isotherm advances quickly and there is not enough time to make the solid network compressible at large cooling ra tes. With decreasing cooling rate, movement of the isotherm is gradual ly slowed and there is enough time to make the network deformed. It is suggested that the compressibility due to the normal stress may produ ce ''channel space'' filled by unstable flow under the conditions of s mall cooling rate during solidification. The calculated results have d emonstrated that the back-flow toward the centerline increases when th e stress is considered.