Ab initio study of the chemical role of carbon within TiAl alloy system: Application to composite materials

Computations within the local spin density functional (LSDF) are carried out for the ternary Ti,Al,C system using the ASW (augmented spherical waves) method to address the chemical role of carbon within TiAl alloy whose electronic structure is firstly investigated. From the preliminary study of the hypothetical compounds formed by insertion and substitution we find carbon to preferably substitute for Al forming Ti-rich phases. The electronic structure of the actually forming carbide Ti 2 AlC compound is then carried out and a role played by carbon is addressed through chemical bonding results using the so-called COOP (crystal orbital overlap populations) implemented for the first time in an LSDF method.