Phase equilibria of the Ti-Al-Nb system at 1400 °C

Abstract

Phase equilibria in the Ti-Al-Nb ternary system at 1400 °C was established, using scanning electron microscopy (SEM), electron backscattered diffraction (EBSD) and electron probe micro-analysis (EPMA). No ternary compound was observed in this work. Compared with the calculated results, the α + β + γ three-phase region moves to higher Nb and Al contents and the σ + β + γ three-phase region moves to a lower Ti content in our experimental results. The tie-triangle of σ + δ + β moves to lower Ti and higher Nb contents. As a result, the homogeneity range of single α phase hugely expands to higher Nb and Al contents and the homogeneity range of single β phase region hugely expands to a higher Al content. The phase regions are also different with the previous reported experimental results.