EXAFS and XRD studies of an amorphous Co$_{57}$Ti$_{43}$ alloy produced by mechanical alloying

Abstract

We have investigated the local atomic structure of an amorphous Co$_{57}$Ti$_{43}$ alloy produced by Mechanical Alloying by means of x-ray diffraction and EXAFS analyses on Co and Ti K-edges. Coordination numbers and interatomic distances where found and compared with those determined using an additive hard sphere (AHS) model associated with a RDF$(r)$ deconvolution, and also with data from bcc-Co$_2$Ti compound. The EXAFS results obtained indicated a shortening in the Co-Ti and Ti-Ti distances when compared to those found by the AHS-RDF method and an increase in the Co-Co and Ti-Ti distances and a large shortening in the Co-Ti one when compared to the distances found in the bcc-Co$_2$Ti compound. In spite of these differences, coordination numbers obtained from EXAFS and AHS-RDF are similar to each other and also to those found in bcc-Co$_2$Ti.