Metadislocations in the complex metallic alloys T-Al-Mn-(Pd, Fe)
by Marc Heggen, Lothar Houben, and Michael Feuerbacher
Novel dislocations were observed in the complex metallic alloys T-Al-Mn-Pd and T-Al-Mn-Fe using high-resolution scanning transmission electron microscopy. The dislocations consist of a large core and separated escort defects. 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 and Burgers vectors. 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-, epsilon6-, and xi-phases is discussed.
Marc Heggen, Lothar Houben, and Michael Feuerbacher, Metadislocations in the complex metallic alloys T-Al-Mn-(Pd, Fe), Acta Materialia 59 (2011) 4458-4466.