Abstract
The slow strain rate technique (SSRT) was used to assess the environmental cracking behavior of TiCode-12, a titanium-base alloy, in a simulated repository brine. The hydrogen effects and electrode potential were examined to understand the alloy's hydrogen embrittlement (HE) and stress corrosion cracking (SCC) behavior. At open circuit, no environment effect was noted, as the results in air and brine were essentially identical. Hydrogen precharging of the samples resulted in a microstructure change, and at very high hydrogen levels, a degradation in mechanical properties. Anodic polarization of the Grade 12 Ti had no effect on mechanical properties, again indicating that the alloy is not susceptible to SCC. Severe cathodic polarization results in a change in both fracture mode and macroscopic stress-strain behavior. However, the conditions under which these changes were observed are considered to be much more severe than those encountered in the proposed repository sites.
