Medium-range ordering and crystallization of CoSiB based alloys with Fe additions

Medium-range order as an intrinsic property of Co-rich amorphous alloys

“…This fact is greatly evidenced in the sample (Fe 0.2 Co 0.8 ) 75 Si 15 B 10 , in which the Fe atoms seems to participate in a bcc-like structure with an atomic ordering that extends to several atomic shells. Indirect evidence of the existence of a strong short-range order around Fe atoms has been recently reported in a crystallization study of CoSiBM (M = Nb, Cr) alloys [3]. These authors show that, when a small amount of Fe is added, the crystallization process begins with the growth of a bcc phase which is suggested to be nucleated in Fe-rich crystal-like clusters present in the amorphous precursor.…”

“…This conclusion can be extended to other Co-based alloys. In particular, the existence of highly ordered structures of Fe must be considered in the study of the crystallization processes of the new Co-rich nanocrystals [3], [11], [12].…”

Differential anomalous scattering on Fe-Co-based metallic glasses

“…Such an ordered Fe-rich phase has been suggested to be the precursor of an Fe bcc phase developed in the first stages of the crystallization process of CoSiBM (M = Nb, Cr) amorphous alloys, when a small amount of Fe enters the composition [10].…”

“…In this paper we use the XRS and DAS techniques to investigate the structure of complex amorphous samples of (Fe x Co 1−x ) 0.75 Si 0.15 B 0.1 (x = 0.2, 0.06) and (Fe 0.08 Co 0.92 ) 0.83 P 0.17 in order to supplement the information obtained in previous EXAFS work [9] with the inclusion of medium-range-order features, and to unambiguously demonstrate the existence of a chemical ordering. The existence or non-existence of ordered structures in the precursor glass is in fact a crucial point in the study of the crystallization processes for the new Co-rich nanocrystals [10][11][12] The paper is organized in the following way: section 2 deals with the formalism of anomalous x-ray scattering; sections 3 and 4 concern the experimental procedure and data analysis; section 5 presents the results and discussion; and finally, section 6 summarizes the main conclusions.…”