Microstructure, strength and irradiation response of an ultra-fine grained FeNiCoCr multi-principal element alloy

Highlights: • An ultra-fine grained FeNiCoCr multi-principal element alloy was fabricated by mechanical alloying and spark plasma sintering. • The FeNiCoCr alloy exhibits high strength and good ductility. • The FeNiCoCr alloy shows enhanced irradiation resistance than conventional Fe–Ni–Cr stainless steels. -- Abstract: An ultra-fine grained (UFG) FeNiCoCr multi-principal element alloy (MPEA) with uniformly distributed nanoscale Cr-rich precipitates was fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). Compression tests show that the yield strength, compressive strength and failure strain of this as-fabricated FeNiCoCr alloy are 1525 MPa, 1987 MPa and 24.4%, respectively. The irradiation response of this alloy was studied following Fe²⁺ ion irradiation with a peak dose of 58 dpa at temperatures of 300 and 500 °C. Our study indicates that the current FeNiCoCr MPEA exhibits modest radiation induced grain boundary (GB) segregation and possesses higher resistance to defects coarsening and void formation compared to conventional Fe–Ni–Cr stainless steels.