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

TL;DR

This study uses EXAFS and XRD to analyze the atomic structure of an amorphous Co57Ti43 alloy produced by mechanical alloying, revealing detailed local atomic arrangements and comparing them with theoretical models and crystalline data.

Contribution

It provides a detailed atomic-level characterization of the amorphous Co57Ti43 alloy using combined EXAFS and XRD techniques, highlighting differences from crystalline structures and models.

Findings

Shorter Co-Ti and Ti-Ti distances compared to AHS-RDF model

Increased Co-Co and Ti-Ti distances relative to bcc-Co2Ti

Similar coordination numbers across methods and with crystalline data

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.