A Small Stress-Corrosion Crack Can Precede a Ductile Final Break

What the evidence preview establishes

Intergranular stress-corrosion cracks initiated at outside edges, grew slowly through a limited portion of the section, and were followed by rapid ductile fracture of the remaining ligament. Ionic surface deposits and possible galvanic interaction were credible corrosion contributors.

Why this case matters

Separate crack initiation and final overload mechanisms. Map intergranular origins and branching, analyze deposits, section beyond the primary fracture, and confirm that apparently brittle service failure was not followed by a ductile final overload.