Internal friction of Niobium-Titanium-Oxygen alloys

The compositional and temperature dependence of the anelastic relaxation behavior in Nb-Ti-O alloys have been investigated. Using a fitting method, the complicated relaxation spectra were resolved into several elementary Debye peaks, which corresponded to the reorientation transitions of O atoms at different octahedral interstitial sites. The number of the peaks depended upon the Ti concentration. The calculation results of the site energies show that the interstitial oxygen atoms preferentially occupy the octahedral interstitial site, which has nearest-neighbor Ti substitutional atoms. Therefore, substitutional Ti solutes will markedly influence the Snoek relaxation behavior in Nb-Ti-O ternary system, even if the concentration of Ti is rather low.