The objective of this proposed research is to investigate the basic mechanisms of transgranular stress corrosion cracking using copper-gold alloys as model systems. This work concentrates on the role of dealloying in crack propagation and nucleation and includes: 1. studies of structural and environmental effects on crack nucleation/propagation and dealloying; 2. relating crack growth rates with the dealloying and repassivation processes; 3. analyses of fracture surface composition and structure; and, 4. dislocation modeling studies of the TSCC process. Techniques used include: Auger electron spectroscopy, x-ray photoelectron spectroscopy, electron microscopy, a.c.-impedance, and laser-Raman spectroscopy.