Relationship between Stress-Corrosion Cracking and Strain Rate in Alpha Brass

Stress-corrosion cracking of Cu-30%Zn alloy under the constant strain rate in the range of 6.6×10^S^ to 1.1×10^S^ was investigated in Mattsson\u27s solution (pH 7.2) (for intergranular cracking) and in 1 M/L NH_4OH+0.25 M/L CuCl_2 aqueous solution (pH 11.0) (for transgranular cracking). Within strain rates of 6.6×10^S^ for intergranular cracking and of 1.1×10^S^ for transgranular cracking, the rate-controlling step of stress-corrosion cracking corresponds to the slip step formation. Exceeding the above strain rates the scc is controlled by the corrosion, where the rate-controlling mechanism requires the activation energy of about 18.7 Kcal/mol. When the strain rate exceeds 1.1×10^S^, intergranular scc never occurs at room temperature. Width of crack tip increases with increase of strain rate for intergranular cracking, while decreases for transgranular cracking