Metal

Quantum mechanics

High-temperature corrosion

High entropy alloys

Metallurgy

Materials science

Intermetallic

Internal oxidation

Laves phase

Thermodynamics

Physics

Diffusion

Alloy

Microstructure

Kinetics

Corrosion

Corrosion Science

The high temperature oxidation behavior of CoCrFeMnNbxNi high-entropy alloys in air was studied. As-cast CoCrFeMnNb0.25Ni alloy is a duplex-phase structure of FCC plus Laves phase. The oxidation kinetics of alloys followed parabolic rate law and the corresponding oxidation rate constants were calculated. In the oxidation process, Nb plays a dual role: On the one hand, the new Laves phase at the oxidation scale/alloy interface hinders the outward diffusion of active metal cations and improves the oxidation resistance; On the other hand, the Laves phase inside the alloy becomes the channel for oxygen ions to diffuse inward and forms internal oxidation.

The role of Nb on the high temperature oxidation behavior of CoCrFeMnNbxNi high-entropy alloys