X-Ray Powder Diffraction Study of Multilayer Polytypes Formation Induced by Mechanical Milling of Laves Phases Co_2+xNb

Intermetallic phase stability on high energy treatments (rapid quenching, ion irradiation and mechanical milling)

“…The stability of a specific crystalline phase with respect to the amorphous state was the only aspect considered in this study. Some of the crystalline metastable phases produced by HET were described earlier in [11][12][13][14].…”

Stability of intermetallic compounds under extreme actions

“…Under some regimes of treatment the accumulation of packing defects can lead to polymorphic transformations. Examples of such a transfbrmation are a polytype transtbrmation (10)--~(33) 2 in alloys of the Co -Nb system with a Laves structure [3] and h (10) --) (1]) transformation in p-phases of the Co -Nb and Ni -Nb -V systems [2]. Both polytypes have not been observed earlier and their structure has been established with the help of an original method [2,3].…”

“…Examples of such a transfbrmation are a polytype transtbrmation (10)--~(33) 2 in alloys of the Co -Nb system with a Laves structure [3] and h (10) --) (1]) transformation in p-phases of the Co -Nb and Ni -Nb -V systems [2]. Both polytypes have not been observed earlier and their structure has been established with the help of an original method [2,3]. The fbnnation of packing defects has been observed in the e-phase of Ni3Nb too, the polytype transformation in which is described by a scheme (1 I)--~ (10).…”

“…The diffraction spectra of phases with packing defects were interpreted using an original approach to the description of some complex crystalline structures (p.-phases like FeTWr Laves phases) [2,3], which allowed us to compute the spectra ['br any phase polytype with various concentrations of strain and twin packing defects.…”