An Electrochemical Mass Transport‐Kinetic Model for Stress Corrosion Cracking of Titanium

The purpose of this work has been to develop a quantitative model for the electrochemical kinetic and mass transport processes in a propagating stress corrosion crack and to use the model to gain insight into manner in which these processes influence propagation. Analysis of the problem led to a system of simultaneous differential equations which with their appropriate boundary conditions were solved by computer implemented numerical methods. Comparison of computed behavior with experimental stress corrosion cracking data for a titanium alloy has guided the development of the model and the specification of critical stress corrosion cracking experiments. Such comparisons indicate that there is a halide ion current to the crack tip with some hydrogen ion discharge in the region downstream from the tip. A significant fraction of the current entering a crack appears to be involved in formation of soluble titanium ions in parallel with oxide formation on the walls.