Study of oxygen content in titanium alloys after exposure at elevated temperature

Abstract

Isothermal oxidation testing of near α titanium alloys VT18U, VT20, Ti6Al7Nb and Ti6242S was performed in air at 560 °С for 1000 hours. Parameters of diffusion layer on the alloy surfaces were studied by microhardness indentations, optical microscopy, X-ray diffraction analysis and nuclear microanalysis. It was established that concentration of oxygen in diffusion layer of tested alloys after oxidation differs significantly. An approach was demonstrated and validated by nuclear microanalysis data that allows comparative evaluation of the total concentration of interstitial impurities in the diffusion layer by the X-ray diffraction method.

Oxidation Effects on Short-Term Creep Response in Air of Commercially Pure Titanium (CP-2 Ti)

“…This evidence confirms that permanence at these temperatures, in the absence of a significant applied stress, did not produce important changes in the microstructure of the annealed plate. The hardening effect illustrated in Figure 3 is fully consistent with similar findings in the literature, which demonstrates that this behavior is due to oxygen diffusion in Ti (see, for example, [9,10]). Thus, a correct estimation of oxygen penetration in the material becomes an interesting point to be analyzed.…”

“…Figure 4a replots the hardness profile of the sample head that experienced the longest permanence at 650 °C (528 h). The figure also includes the value of the hardness in The hardening effect illustrated in Figure 3 is fully consistent with similar findings in the literature, which demonstrates that this behavior is due to oxygen diffusion in Ti (see, for example, [9,10]). Thus, a correct estimation of oxygen penetration in the material becomes an interesting point to be analyzed.…”