Dislocation properties of polycrystalline Fe-Cr-Al alloys and their correlation with mechanical properties

The microstructure of four Fe-Cr-Al alloys containing 9.3-18.0 at.% chromiu m and 25.5-7.6 at.% aluminum has been investigated by transmission electron microscopy after different heat treatments and different degrees of compre ssive deformation. The properties of single dislocations and their arrangem ent in different states of deformation are discussed with respect to the co rresponding state of order and work-hardening curves. The maximum of the wo rk-hardening curves is shifted to higher strains with increasing aluminum c oncentration. The transition from increasing to decreasing work-hardening i s correlated with a change of the dislocation arrangement from planar to no n-planar. A significant effect of vacancy formation on the dislocation stru cture and deformation process could not be observed. At a deformation tempe rature of 400 degrees C dynamic strain aging occurs. (C) 2000 Elsevier Scie nce S.A. All rights reserved.