ON THE ORIENTATION-DEPENDENT GRAIN-BOUNDARY MIGRATION IN AN FE-6AT.PERCENT-SI ALLOY

The [100] symmetrical tilt grain boundaries in an Fe-6at.%Si alloy wer e found to exhibit a pronounced anisotropy of activation enthalpy of m igration characterized by its high values for special boundaries as co mpared to general ones. This rather surprising result is explained on the basis of extended model of Gottstein and Shvindlerman supposing th ree main contributions to the migration enthalpy: intrinsic migration enthalpy, migration enthalpy resulting from grain boundary segregation , and migration enthalpy resulting from alloy mixing. It is shown that the differences in migration enthalpy of special and general grain bo undaries in a concentrated alloy reflect the prevailing character of t he intrinsic migration enthalpy over the weakened segregation effects.