Stress corrosion cracking of Cu–30% Zn alloy in Mattsson’s solutions at pH 7.0 and 10.0 using constant load method – A proposal of SCC mechanism

The stress corrosion cracking (SCC) of a commercial Cu–30% Zn alloy has been investigated as a function of applied stress in Mattsson solutions with pH 7.0 and 10.0 at 313 K by using a constant load method. It was found that the elongation behavior at pH 10.0 showed clearly the step wise fashion, while that at pH 7.0 did slightly, almost over the whole applied stress. The steady state elongation rate obtained from corrosion elongation curve became a relevant parameter for predicting time to failure. Furthermore, from the results obtained, it is deduced that a unified SCC mechanism is qualitatively proposed to explain both of transgranular SCC (TGSCC) at pH 10.0 and intergranular SCC (IGSCC) at pH 7.0, where the unified SCC mechanism is basically based on a film rupture-formation event at crack tips.