Constitution of Ni–Al–Ti system studied by scanning electron microscopy

The Ni–Al–Ti system is one of the key model systems for technically important materials based on nickel and titanium aluminides. A recent critical literature review by Schuster stated a lack of experimental data apart from corners of the composition triangle. This work is focused on several alloys of Ni–Al–Ti system from the central part of the composition triangle, where numerous intermetallic phases coexist. The microstructure of alloys was studied and quantified after long term annealing at 1050 °C by means of scanning electron microscopy with an energy dispersive X-ray analysis and electron backscatter diffraction. Experimental results were compared with existing literature data. In order to compare experimental knowledge on phase equilibria with results of thermodynamic modelling, phase diagram was calculated using the software package ThermoCalc and two different thermodynamic databases.