Microbeam analysis of hydrogen near a crack tip in titanium

Microbeam transmission elastic recoil detection (ERD) was used to analyze microscopic hydrogen distributions near a crack tip in Ti foil loaded with an initial atomic hydrogen concentration of 3.0% relative to Ti. A 5.8MeV He ion beam focused down to the order of 10μm was scanned in a 500μm line perpendicular to the crack and approximately 20μm ahead of the crack tip. ERD line maps were made for a series of increasing stresses which were applied by uniaxial tension perpendicular to the crack. The crack opening displacement (COD) for each stress load was measured from an ion-beam-induced secondary electron emission (SEM) spectrograph of the crack opening. The technique was used to characterize the fracture mechanical properties of α-Ti hydride and demonstrates the use of microbeam analysis for the study of binary hydrogen metal systems.