This study investigates phase equilibria within the Al–Ti–Nb–Zr–Ta refractory complex concentrated alloy (RCCA) system using a high-throughput combinatorial experimental approach. A pseudo-ternary section was fabricated via a honeycomb-type powder metallurgy design, consolidated through spark plasma sintering (SPS), and subjected to homogenization at 1400°C for 168 hours. Phase constitution and chemical partitioning were characterized using an integrated suite of SEM/EDS, EBSD, and TEM, supported by a custom EDS phase-clustering workflow [1]. Structural analysis was further refined through X-ray diffraction (XRD) utilizing both 1D linear and 2D area detectors; the latter proved essential for identifying significant preferential orientation (texture) and grain coarsening induced by the prolonged high-temperature annealing.
Equilibrium microstructures across the sampled compositions consisted primarily of BCC and B2 phases, with nanoscale precipitates forming in Zr- and Ta-rich regions. Experimental phase compositions were compared with CALPHAD predictions, revealing consistent systematic deviations that highlight current limitations in multicomponent thermodynamic databases. These results provide critical insights into the phase stability and microstructural trends of the Al–Ti–Nb–Zr–Ta system while demonstrating the efficacy of high-throughput methods and multidimensional XRD analysis in mapping complex alloy spaces.