High-Throughput Synthesis and Characterization of a Combinatorial Materials Library in Bulk Alloys

Aiming for the accelerated screening of promising materials for a variety of engineering applications efficiently and cost-effectively, a novel high-throughput micro-synthesis of a combinatorial material library through hot isostatic pressing was reported herein. As Co, Fe and Ni are the most common base and alloying elements in metallic alloys and particularly in high entropy alloys, a Co-Fe-Ni ternary alloy system was selected for the study. Using high-purity elemental metal powders as stock materials, 19 combinatorial alloy compositions were designed, and their powder mixtures were placed and vacuum sealed in the cell space of a set of customized honeycomb arrays made of Ni or Ti foils. Subsequent consolidation was conducted under hot isostatic pressing at 1050 °C at 120 MPa for 10 hours. Each of the as-made bulk alloys was characterized by microscopy and spectroscopy, exhibited no macro defects, had actual compositions comparable to the nominal ones, and generated phase constituients and microstructure comparable to these via traditional processes for bulk alloys. The composition and phase constitution of these alloys were systematically characterized, and the discrepencies comparing to historical data were ascribed to the thermodynamic and kinetic driving forces in the processing. The present method, i.e. high-throughput synthesis and characterization of a combinatorial materials library in bulk alloys, demonstrated a new way for screening alloy compositions, microstructures and properties.