What term describes brittle failure in an otherwise ductile material due to the combined action of tensile stress and a corrosive environment?

• A. Hydrogen-induced cracking
• B. Stress corrosion cracking (SCC)
• C. Pitting corrosion
• D. Crevice corrosion

Answer: (B)

Stress corrosion cracking describes brittle failure in a ductile metal when a susceptible material is exposed to a specific corrosive environment while under tensile stress. The three conditions—susceptible material, a corrosive environment, and sustained tensile stress—must be present for this type of cracking to occur. At the crack tip, environmental reactions may cause anodic dissolution or hydrogen uptake, weakening the metal and allowing crack growth with little plastic deformation. This leads to a brittle-looking fracture under loads that wouldn’t cause such failure in a non-corrosive environment, often propagating along grain boundaries or through grains. By contrast, pitting and crevice corrosion are localized surface attacks without the same crack propagation under load, and hydrogen‑induced cracking is a specific embrittlement mechanism that can contribute to SCC but is a narrower case within the broader phenomenon.