High-temperature stability of α-Ta4AlC3

Cold-pressed α-Ta4AlC3 powders were annealed up to 1750 °C to test first-principles predictions of α–β phase-stability reversal at 1600 °C. Up to 1600 °C, the α-Ta4AlC3 samples were stable with no indications of any α–β transformation, as shown by the strong characteristic X-ray diffraction peaks of α-Ta4AlC3 and the zigzag stacking observed by transmission electron microscopy. These results show that, in this experimental situation, high temperature alone is not sufficient to cause the α–β transformation.