Influence of Impurities on the Stability of the Ti5Si3 and TiSi Phases.

The total energies of a number of Ti–Si intermetallic phases are calculated by the projector augmented-wave method. It is shown that the formation enthalpies of Ti₅Si₃ and TiSi are almost equal. The peculiarities of the density of electronic states of the considered titanium silicides and its evolution with increasing silicon content are discussed. The formation energies of doped titanium silicides Ti₅Si₃ and TiSi are calculated depending on the position of the impurity on different sublattices. It is established that the elements of the 3d-period prefer to replace titanium in Ti₅Si₃, while the elements of the second half of the 3d‑period substitute silicon in TiSi. The effect of impurities on the relative stability of compounds is studied. It is shown that almost all the considered elements except Cu, Zn, Al, and Ga increase the stability of the Ti₅Si₃ phase with respect to TiSi. The obtained results agree with the available experimental data. [ABSTRACT FROM AUTHOR]