PHASE-RELATIONSHIPS IN THE AL-TA SYSTEM

Phase relationships have been investigated in the Al-Ta system in the region between Al and AlTa2. Al-Ta alloys with compositions between 20 and 60 at. pct Ta were prepared using different processing routes. Following appropriate heat treatments, the alloys were characterized microstructurally, by quantitative electron probe microanalyses, X-ray diffraction, and differential thermal analysis. Based on our observations, a revised Al-Ta phase diagram is proposed. Significant revisions include the verification of Al3Ta as a line compound, the absence of a eutectic transformation in the region between Al3Ta and AlTa2, and the conclusive identification of a phase designated as AlTa near the equiatomic composition. © 1990 The Metallurgical of Society of AIME.