Internal Friction Measurements in Nb-0.3 wt. % Ti Containing Oxygen

Abstract

Internal friction measurements were made in the Nb-Ti alloy containing 0.3 wt. % of Ti, doped with various quantities of oxygen (0.04 to 0.08 wt. %) utilizing a torsion pendulum. These measurements were performed in the temperature range of 300 K to 700 K with the oscillation frequency about 1.0 Hz. The experimental results showed relaxation peaks due the stress induced ordering of oxygen atom and pairs of oxygen atom around the niobium atoms (metallic matrix) and around titanium atoms (substitutional solute).

Activation Energy Measurement of Oxygen Ordering in a Nb-Ti Alloy by Anelastic Relaxation

“…The first indication underpinning the validity of this as- These results are in reasonable agreement with previously published results 2,5,8,10 , reinforcing our initial supposition.…”

“…The samples in question are polycrystals of a Nb-Ti alloy having 0.3% in weight of Ti (Nb -0.3% Ti), produced by the Materials Engineering Department, Lorena Faculty of Chemical Engineering (FAENQUIL), by mechanical mixing of Nb and TiO 2 powders followed by cold isostatic pressing and high vacuum sintering 10 . The samples are cylinder-shaped, with a 1.3 mm diameter for 45 mm of useful length.…”

“…Today, more than fifty years after the discovery of the "Snoek Peaks", studies are still being made to clarify the relaxation mechanisms in pure metals 8,9 and metallic alloys such as Nb-Ti 10,11 and Nb-Zr 12,13 . Our main objective with this work is the systematic study of anelastic relaxations caused by stress-induced ordering of heavy interstitial solutes present in metallic matrices of niobium-based alloys, such as Nb-Ti, using internal friction measurements based on the torsion pendulum technique.…”

Anelastic relaxation processes due oxygen in Nb–3.1 at.% Ti alloys

“…The third relaxation at high temperature is ascribed to nitrogen (Nb-N Snoek peak), which represents the second interstitial impurity content of the alloy. The activation enthalpy for the three processes proposed was fixed, based in values determined earlier by internal friction experiments [11][12][13] Table 2. The fact that that the peak temperatures and frequency of the processes at lower and middle temperatures do not fit the Arrhenius plots of Nb-O relaxation [3] and of the Ti-O relaxation [9] can be explained considering that, at high concentration, the substitutional Ti markedly perturbs the periodic potential of the interstitial sites so affecting the relaxation parameters of the processes [14].…”

Measurement of oxygen atom diffusion in Nb and Ta by anelastic spectroscopy

“…Consequently, peak identification does not present a particular problem. In contrast, some arguments as to whether "clustering" and "anticlustering" occurs with increasing oxygen content [13][14][15][16][17][18][19] have been raised. The clustering model proposes the formation of oxygen pairs and other oxygen clusters 13 , while the anticlustering model proposes a long-range repulsive interaction between oxygen interstitials and the possibility of some interaction between different types of heavy interstitials, such as oxygen and nitrogen 14 .…”