ROOM-TEMPERATURE DEFORMATION MODES IN DO3-STRUCTURED FE-34AL AND FE-28AL-6CR

The dislocation substructures in the DO3-structured alloys, Fe-34Al an d Fe-28Al-6Cr, were examined by transmission electron microscopy follo wing room temperature compression. In both alloys a small number of a[ 001] dislocations, produced through the energetically favourable inter action of two pairs of antiphase boundary-coupled a/2[111] dislocation s, was observed. It was also found that, relative to the binary alloy, one effect of the chromium addition was to increase the B2 character of the alloy, but conversely to decrease the DO3 character. These resu lts are rationalized on the basis of the atom site location of the chr omium atoms in the DO3 structure.