Phase equilibria at 1100 °C in the Nb–Ti–Al system

The phase equilibria at 1100 °C has been examined as part of a larger investigation of the phase equilibria and transformations within the Nb–Ti–Al system. Fifteen alloys ranging in composition from 15 to 40 at.% Al, with Nb:Ti ratios of 1:1.5 up to 4:1, were prepared by arc-melting. The alloys were homogenized and solution treated in the β (bcc) solid solution phase field prior to heat treatment at 1100 °C, and the microstructures characterized by optical microscopy, X-ray diffraction (XRD), electron probe microanalysis, scanning and transmission electron microscopy (TEM). The phase equilibria will be discussed along with a comparison with earlier experimental work.