Accelerated discovery of oxidation resistant CoNi-base γ/γ' alloys with high L12 solvus and low density

A systematic and accelerated methodology for alloy design is demonstrated by combining combinatorial synthesis, high-throughput oxide scale characterization, computational density functional theory, and CALPHAD database calculations. By applying this strategy to the senary Co-Ni-W-Al-Cr-Ta material system, a novel gamma/gamma'alloy exhibiting a superior combination of properties has been identified. Properties include a gamma' solvus near 1200 degrees C, continuous alpha-Al2O3 scale formation after 1 h in air at 1100 degrees C, and comparable density to 2ndgeneration commercial Ni-base superalloys. This novel alloy SB-CoNi-10 has a nominal composition of 39.8Co - 36.5Ni - 13.2Al- 1.0W - 6.0Cr - 3.5Ta at.%, and its properties are compared with other recently studied Co-, CoNi-, and Ni-base gamma/gamma' alloys. (C) 2020 The Authors. Published by Elsevier Ltd.