EXAFS and XRD studies of an amorphous Co57Ti43 alloy produced by mechanical alloying

We have investigated the local atomic order of an amorphous Co57Ti43 alloy produced by mechanical alloying by means of x-ray diffraction and EXAFS analyses on Co and Ti K-edges. Average coordination numbers and average interatomic distances between first neighbors where found from EXAFS and compared with those determined using an additive hard sphere (AHS) model associated with an RDF(r) deconvolution, and also with data from bcc-Co2Ti compound. EXAFS results obtained indicated a shortening in the Co-Ti and Ti-Ti average interatomic distances when compared to those found by using the AHS-RDF method and an increase in the Co-Co and Ti-Ti average interatomic distances and a shortening in the Co-Ti one when compared to the interatomic distances found in the bcc-Co2Ti compound. In spite of these differences, average coordination numbers obtained from EXAFS and AHS-RDF are similar to each other and also to those found in bcc-Co2Ti. (c) 2007 Elsevier Ltd. All rights reserved.