Based on the excellent comprehensive mechanical properties of high–entropy alloy (HEA), the NiAl-based HEA was designed to achieve excellent high-temperature strength, toughness, and wear resistance. In this work, vacuum arc melting technology was used to prepare (NiA1)₇₈(CoCrFe)_16.5Cu_5.5 HEA, and its microstructure, phase composition, and mechanical properties were systematically studied. The results showed that (NiA1)₇₈(CoCrFe)_16.5Cu_5.5 HEA was composed of FCC and BCC/B2, with a spinodal decomposition structure in the matrix, and nano-precipitation in the interdendritic, exhibiting a good high-temperature performance. At 600 °C, the compressive fracture strength is 842.5 MPa and the fracture strain is 24.5%. When the temperature reaches 800 °C, even if the strain reaches 50%, the alloy will not fracture, and the stress–strain curve shows typical work hardening and softening characteristics. The wear coefficient of the alloy first increases and then decreases with the increase in temperature in the range of room temperature to 400 °C. However, the specific wear rate shows the opposite trend. At 100 °C, the wear rate reaches the lowest of 7.05 × 10⁻⁵ mm³/Nm, and the wear mechanism is mainly abrasive wear.

In this work, two alloys of Ni₃₅Al₃₀(FeCo)₂₅Cr_10-xMo_x (x = 0, 5) were prepared via the vacuum arc melting method, and the effects of Mo on the microstructure, mechanical properties, and friction and wear properties of the alloys were investigated. The addition of Mo improved the mechanical properties, wear resistance, and corrosion resistance of the alloy system. With the addition of trace amounts of Mo, the precipitate phase of the alloys transformed from spherical to acicular and plate-like. The precipitated phases in a co-lattice relationship with the matrix allow for a substantial increase in the strength of the alloy at both room and elevated temperatures without a significant loss of plasticity. Ni₃₅Al₃₀(FeCo)₂₅Cr₅Mo₅ has excellent mechanical properties, with a hardness of 558.2 HV; a yield strength of 1320 MPa at 600 °C; and a yield strength of 537 MPa at 850 °C. As the temperature increased, the wear mechanism changed from abrasive wear to adhesive wear. At 600 °C, Ni₃₅Al₃₀(FeCo)₂₅Cr₅Mo₅ had the lowest wear rate of 1.78 × 10⁻⁵ (mm³/Nm). The precipitated phases, which have high hardness and maintain a conformal interface with the matrix, play an important role in slowing delamination wear, keeping the wear rate of this alloy low at both room and high temperatures. Electrochemical experiments on the two alloys at room temperature revealed that Ni₃₅Al₃₀(FeCo)₂₅Cr₅Mo₅ exhibited excellent resistance to pitting, with a pitting potential of 0.016 V.