Microstructure and Tensile Behavior of Al8Co17Cr17Cu8Fe17Ni33 (at.%) High-Entropy Alloy

On the Path to Optimizing the Al-Co-Cr-Cu-Fe-Ni-Ti High Entropy Alloy Family for High Temperature Applications

“…Finally, tensile tests on three of the six alloys, namely Alloy 1 [23], Alloy 4 [18], and Alloy 6 [24] give a last tool for comparing the alloys (see Figure 6). Tensile tests have been carried out at different temperatures and the obtained data has been compared with that of commercial alloys like Alloy 800H [25] and Inconel 617 [26].…”

High-Temperature Tensile Strength of Al10Co25Cr8Fe15Ni36Ti6 Compositionally Complex Alloy (High-Entropy Alloy)

“…8,9 The first can be tested under a tensile load, but their strength values are small. 7,10 The latter show high compressive strength up to 1000°C, 8,9 but because of their brittleness, these alloys cannot be tested in tension. However, a new high entropy alloy with hexagonal close-packed (hcp) solid solution has been recently published.…”

“…This strengthening effect is explained by precipitate hardening, the temperature anomalous behavior of L1 2 precipitates, and coherency stresses. 11,12 From our previous work, 10 we identified the alloy Al 8 Co 17 Cr 17 Cu 8 Fe 17 Ni 33 (in the following named ''initial fcc alloy'') to be promising because of the following properties: Its microstructure consists of a matrix with fcc structure containing about 20 vol.% of c¢ precipitates with an ordered L1 2 structure and with a diameter smaller than 20 nm; it shows high elongation to failure under tensile load; and it exhibits very good oxidation resistance up to 1000°C in air. 13 The challenge now is to enhance its low strength by increasing the size and volume fraction of the c¢ precipitates.…”

“…1,2 Additionally, Cu has been completely eliminated in the new optimized alloy to inhibit the formation of a Cu rich fcc phase, which was observed in the previously studied ''initial fcc alloy'' Al 8 Co 17 Cr 17 Cu 8-Fe 17 Ni 33 . 10 Finally, the Cr content has been reduced to eliminate the formation of brittle r phases, leading to a brittle alloy. 10,13 Thus, a new ''optimized fcc alloy'' with the composition Al 10 Co 25 Cr 8 Fe 15 Ni 36 Ti 6 (at.%) has been selected by CALPHAD calculations (Thermo-Calc with TTNi7 database 15,16 ) of 190 different alloys.…”

“…10 Finally, the Cr content has been reduced to eliminate the formation of brittle r phases, leading to a brittle alloy. 10,13 Thus, a new ''optimized fcc alloy'' with the composition Al 10 Co 25 Cr 8 Fe 15 Ni 36 Ti 6 (at.%) has been selected by CALPHAD calculations (Thermo-Calc with TTNi7 database 15,16 ) of 190 different alloys. In this work, we present the mechanical properties of the optimized alloy Al 10 Co 25 Cr 8 Fe 15 Ni 36 Ti 6 under a tensile load at different temperatures.…”