The Polythermal Section of Ti-22Al-<i>x</i>Nb (30-78at.%Ti) in Ti–Al–Nb System

Abstract

The polythermal section of Ti-22Al-xNb (30–78 at.% Ti) in the Ti-Al-Nb system was studied using X-ray diffraction analysis (XRD), differential thermal analysis (DSC), and electron probe micro-analysis (EPMA). No new ternary compounds were found in this work. The polythermal section has five three-phase regions, nine two-phase regions, and three single-phase regions. The O phase transition is confirmed to occur below 1000 °C. A four-phase invariant reaction β + σ → O + δ was found at 931 °C.

Keywords

• Ti-Al-Nb system
• phase diagram
• polythermal section