Effect of crystal defects on solute atoms segregation during cooling

Different quantity and configurations of crystal defects were obtained in a n austenite of Fe-30%Ni alloy and an ultra low carbon bainitic steel by dif ferent deformations and annealing times at high temperature. The boron segr egation at grain boundaries and subgrain boundaries during air cooling were revealed by means of particle tracking autoradiography technique. It was f ound that the non-equilibrium segregation was resisted in the deformed grai ns after recovery and polygonization, the boron depletion was more in the r ecrystallized grains than in the deformed original grains during the coolin g. The subgrain boundaries and polygonized dislocation cells had a signific ant effect on the boron non-equilibrium segregation during the air cooling, but the quantity of dispersed dislocations had not. The result indicated t hat during segregation process the interaction of boron atoms with dislocat ions was sensitive to the dislocations configuration rather than the total number of defects in grain. (C) 2001 Kluwer Academic Publishers.