New insights into the oxidation and reduction behavior of two-phase (α2 + γ) TiAlNb and TiAlTa alloys and their components

The purpose of the paper is to present the basic mechanism of oxidation and reduction of Ti-46Al-8Nb and Ti-46Al-8Ta alloys using the temperature programmed oxidation and reduction method (TPOx-TPR) supplemented and supported with the X-ray diffraction analysis (XRD), scanning and transmission electron microscopy observations (SEM, TEM) equipped with the Energy-dispersive X-ray spectroscopy (EDS). A broader view of the alloys’ behavior was obtained through the analysis performed for powders and solid samples of the alloys itself, but also of the single metals that constituted the alloys. The presented results can be helpful for better understanding of alloys behavior in contact with high-temperature oxidizing/reducing atmosphere in the context of their constructional applications. Moreover, powder analysis can provide valuable information before planning the additive manufacturing of titanium aluminides alloys. In addition, the superior influence of tantalum in comparison to the niobium additive in terms of alloys oxidation is discussed and questioned in the following paper.