Exceptional combination of mechanical properties and cavitation erosion-corrosion resistance in a Fe23.7Co23.8Ni23.8Cr23.7Mo5 multi-principal element alloy

This study analyzed cavitation erosion (CE) and cavitation erosion-corrosion (CE-C) of single-phase face-centered cubic structured Fe23.7Co23.8Ni23.8Cr23.7Mo5 multi-principal element alloy (MPEA) with varying grain sizes obtained through post-deformation annealing (PDA). The average grain sizes of the samples after annealing at 1100 °C for 60s, 1150 °C for 60s, and 1100 °C for 200s are 4.1 μm, 10.3 μm, and 15.2 μm, respectively. Among them, the 4.1 μm sample exhibits the best combination of high ultimate tensile strength (889MPa) and large elongation (40.3%), as well as good electrochemical corrosion resistance in NaCl solution. Under the conditions of CE and CE-C for a duration of 10h, the 4.1 μm specimen exhibits cumulative mass losses of approximately 1.4mg and 2.6mg, respectively. In contrast, under identical conditions, the 316L SS registers cumulative mass losses of approximately 16.7mg and 24.8mg, respectively. Due to the excellent mechanical properties and work hardening ability of the 4.1 μm sample, it can effectively resist the plastic deformation caused by cavitation erosion, reducing mass loss. In addition, the stable passivation film enhances its resistance to Cl- destruction, thus demonstrating notable corrosion resistance. Ultimately, under conditions where cavitation erosion and corrosion coexist, these combined properties enable the 4.1 μm sample to exhibit the least mass loss and damage.