Research Progress on the Point-defect Relaxation in β-Ti Alloys

Abstract

The anelastic relaxation is measured at a low and high frequency from low to high temperature in some Ti alloys, most of which are usually recorded in the internal friction-temperature spectra. In this paper, the point-defect relaxation in β-Ti alloys is described and discussed. The point defects are the interstitial impurity atoms, substitution atoms and vacancies in β-Ti alloys. The reorientation of interstitial impurity O atoms around matrix Ti and substitute atoms produces Snoek-type peaks. The various interactions between the interstitial impurity atoms (O,N,et al.) and matrix atoms/substitute atoms (Ti, Nb,Mo,V,et al. ) can also produce a complex relaxation spectra consisting of several Snoek-type peaks. The concentrations of interstitial impurity atoms and the substitute atoms have important roles on the height and width of the Snoek-type peaks. The reorientation of defect pairs consisting of the interstitial impurity atoms and vacancies is also involved in the relaxation processes. At high temperatures, the Mo-Mo atom-pairs can be reoriented under the inducing of cycle stress and produce similar Zener relaxation peak.