On the Initiation and Growth of Stress Corrosion Cracks in Tarnished Brass

Stress corrosion cracking of α‐brass was studied in nearly neutral ammoniacal copper sulfate. Under the test conditions, this solution produced a thin, adherent oxide film on the brass. Microstructural studies of the fracture surfaces suggest that alternate formation and rupture of this film leads to initiation and propagation of stress corrosion cracks. Crack propagation rates were measured in sheet specimens with a central notch and found to be proportional to , where is the applied stress and l is the semicrack length.