Achieving High-Temperature Oxidation and Corrosion Resistance in Fe–Mn–Cr–Al–Cu–C TWIP Steel via Annealing Control

Twinning-induced plasticity (TWIP) steel shows great potential in engineering due to its excellent strength and ductility synergy, and strengthening research on its corrosion resistance and high-temperature oxidation resistance is critical for broader applications. Herein, the effect of annealing temperature on the high-temperature oxidation and corrosion behavior of Fe–Mn–Cr–Al–Cu–C TWIP steel is investigated. The results show that increasing the annealing temperature from 700 °C to 1100 °C reduced the mass gain of the TWIP steel oxidized at 800 °C for 8 h from 1.93 to 0.58 mg·cm⁻². Additionally, the self-corrosion current density decreases from 6.52 × 10⁻⁶ to 1.32 × 10⁻⁶ A·cm⁻², while charge transfer resistance increases from 1461 to 3339 Ω·cm⁻². The reduction in grain boundaries and dislocation density in the TWIP steel attributed to the increase in annealing temperature inhibits short-circuit diffusion, local galvanic corrosion and pitting, ultimately improving both oxidation and corrosion resistance. Moreover, high-temperature annealing prevents the formation of carbon-rich compounds and ensures uniform element distribution. The accumulation of Cu and Cu-rich products formed at the interface further protects against Cl⁻ erosion, inhibiting pitting and local corrosion, thus enhancing the corrosion resistance of the TWIP steel.