Stress corrosion cracking and precipitation strengthening mechanism in TWIP steels: progress and prospects

Abstract Twinning-induced plasticity (TWIP) steels are increasingly receiving wide attention for automotive applications due to their outstanding combination of ductility and strength, which can largely be attributed to the strain hardening effect, formation of mechanical twins during straining, and the presence of manganese (Mn) as an alloying element. However, the premature cracking and sudden failure frequently experienced by the TWIP steels under the combined action of tensile stress and corrosion environment remain a challenge for many material scientists and experts up till now. Driven by this challenge, an overview of the stress corrosion cracking (SCC) susceptibility of high-Mn TWIP steels (under the action of both mechanical loading and corrosion reaction) is presented. The SCC susceptibility of the high-Mn TWIP steels is specifically sensitive to hydrogen embrittlement, which is a major factor influencing the SCC behavior, and is a function of the hydrogen content, lattice-defect density and strength level. Besides, the corrosion susceptibility to hydrogen embrittlement may be reduced by suppressing the martensite in the TWIP steels by carbon additions. This review further discusses in detail the precipitation strengthening mechanisms as well as the corrosion behavior of TWIP steel by mechanism.