DISLOCATION FEATURES IN FeAl INTERMETALLIC COMPOUND AFTER DEFORMATION AT HIGH TEMPERATURE

The dislocation features in FeAl intermetallic compound deformed at 900℃have been investigated by TEM.A large number of sqaure dislocation loops and helical dipoles have been found.The loops are identified to have the Burgers vector[100] and lie on(100)planes due to vacancy condensation. The helices are identified to have the Burgers vector [111] and result from the climb process of screw [111] dislocation at high temperature.One evidences indicate that further climb of the helical dipoles could result in another kind of loop which has the same Burgers vector as the dipoles and lies on the planes perpendicular to the Burgers vector.It is assumed that the climb of dislocation is responsible for the high ductility of FeAl compound at high temperature.