Construction of Ti-Al-Cr phase diagram using quantitative X-ray microanalysis in analytical electron microscope

This paper describes determination of the Ti-Al-Cr ternary phase diagrams using quantitative X-ray microanalysis in analytical electron microscopy. Alloys with several different compositions were subjected to heat treatments for equilibration at 1273 and 1473 K. Microstructural observations and selected area electron diffraction analyses were conducted for phase identification and characteristic X-rays were measured from each phase. The characteristic X-ray intensities were then converted to concentrations using the ζ-factor method while the absorption correction was simultaneously achieved with this method. It was found that the three-phase regions such as α₂ + B2 + γ, B2 + γ + Laves and γ + Laves + L1₂ were present at 1273 K, whereas at 1473 K, no Laves phase was observed and disordering occurred from the α₂ and B2 phases to the α and β phases, respectively. Thus, the three-phase regions were present as α + β + γ and β + γ + L1₂ at 1473 K. The α + β + γ and β + γ regions were extended to a lower Al concentration as the temperature decreases.