Correlation of microstructure, mechanical properties and corrosion behavior in a Ni34Co28Cr28Al10 multi-principal element alloy with outstanding corrosion resistance

Microstructure, mechanical properties and corrosion behavior of a Ni34Co28Cr28Al10 multi-principal element alloy (MPEA) were investigated at different states. The as-cast and aged samples exhibited a primary face-cubic centered (FCC) phase and some B2 phase, wherein the FCC phase contained L12 precipitates and the B2 phase contained body-cubic centered (BCC) precipitates. The homogenized sample displayed a single FCC phase. The as-cast sample exhibited the best combination of mechanical properties and corrosion resistance, resulting from multiple strengthening mechanisms, and Al-rich L12 and B2 precipitates which could suppress the transfer of Al atoms to surface leading to increased Cr content in passive film.