Effect of Corrosive Environment on Crack Propagation in Alpha Brass and a Copper-Beryllium Alloy Available to Purchase

Notched specimens of a copper-beryllium alloy and of α-brass were tested in tension in an ammonia-containing solution. Specimens were strained at rates ranging from 0.5 cm/min to 5 × 10⁻⁴ cm/min. Formation of a plastically deformed zone at the root of the notch appears to be essential to the formation and propagation of the crack. A smaller amount of plastic deformation was needed to start a crack in the corrosive solution than in air. The observation that the effect of the corrosive solution seems to be independent of the strain rate suggests that an adsorption process contributes to specimen failure in stress corrosion fracture.