Enviromechanical Testing of Ti-grade 2 and Ti-grade 12 in Basalt Groundwater

In earlier corrosion screening studies, Ti-grade 2 and Ti-grade 12 were found to have exceptional resistance to uniform corrosion in basalt groundwater. Further rigorous tests were then applied to characterize the resistance of these materials to degradation induced by groundwater radiolysis and by application of stress in the presence of the groundwater environment.

These tests included irradiation-corrosion tests (using corrosion coupons, U-bend specimens, Charpy V-notch impact specimens, and bolt-loaded fracture specimens), slow strain rate (SSR) tests, and fatigue crack growth rate (FCGR) tests.

Results of the current study suggest that Ti-grade 2 and Ti-grade 12 could be suitable for use as long-lived engineered barriers in a basalt repository. Further studies are needed, however, including a detailed analysis of the tendency of the materials to absorb hydrogen. This paper describes the testing of Ti-grade 2 and Ti-grade 12 by corrosion and irradiation-corrosion tests, SSR tests, and FCGR tests.