The low-temperature (less than one-fourth of the melting temperature) creep deformation behavior of hexagonally close-packed α-Ti–1.6wt%V was investigated. Creep tests were performed at various temperatures between room temperature and 205C at 95% of the respective yield stress at the different temperatures. The creep strain rate was found to increase with increasing temperature. Scanning and transmission electron microscopy revealed that slip and unusually slow twin growth, or time-dependent twinning, were active deformation mechanisms for the entire temperature range of this investigation. The activation energy for creep of this alloy was calculated to identify the rate-controlling deformation mechanism, and was found to increase with increasing creep strain. At low strain, the activation energy for creep was found to be close to the previously calculated activation energy for slip. At high strain, the calculated activation energy indicates that both slip and twinning were significant deformation mechanisms. The appearance of twinning at high strains was explained by a model for twin nucleation by dislocation pileups.

The Effect of Time-Dependent Twinning on Low Temperature (<0.25Tm) Creep of an Alpha-Titanium Alloy. P.G.Oberson, S.Ankem: International Journal of Plasticity, 2009, 25[5], 881-900