Al_xCoCrFeNi high entropy alloys with superior hot corrosion resistance to Na_2SO_4 + 25% NaCl at 900 °C

摘要

Hot corrosion behaviors of Y, Hf-codoped AlxCoCrFeNi (Alx, x = 0.7, 1.0, and 1.3) high-entropy alloys (HEAs) under Na2SO4 + 25 % NaCl molten salts at 900 degrees C were investigated and compared with those of the conventional NiCoCrAl alloy. The results show Al1.0 and Al1.3 with spinodally decomposed structure of A2 + B2 phases possess significantly enhanced hot corrosion resistance than Al0.7 with eutectic lamellar structure and NiCoCrAl. The superior hot corrosion resistance is attributed to the loop-locked coherent phase interfaces in the modulated structure, along with the improved availability of Al and the high Cr content.