Metadislocations in the complex metallic alloys T–Al–Mn– (Pd, Fe)

Abstract We investigate dislocations in the complex metallic alloys T–Al–Mn–Pd and T–Al–Mn–Fe using high-resolution aberration-corrected scanning transmission electron microscopy. The dislocations consist of a large core and separated escort defects [1] . Upon movement, dislocations and escort defects locally transform the material and introduce stacks of planar faults which represent a slab of a different but related structure. Deformation modes involving glide and climb are observed. We find different types of dislocations with Burgers vectors b → = - ( - τ ) - n ( 0 0 1 ) , with n = 2, 3, 4. They are associated to two, four and six planar faults, respectively, and are identified as metadislocations. The structural connection between metadislocations in the present phase and those in R-, e6-, and ξ-phases is discussed.