Probing the effect of solute hydrogen and hydrides on the prismatic slip of [21‾1‾0]-orientated alpha titanium using in-situ micropillar compression

In-situ micropillar compression tests were performed on the [ 2 1 ¯ 1 ¯ 0 ] -oriented alpha titanium micropillars to investigate the effect of solute hydrogen and titanium hydrides on the activation of prismatic slip ( 〈 11 2 ‾ 0 〉 { 10 1 ‾ 0 } ) . The formation of the hydride phase and the deformation mechanisms in air, in the presence of solute hydrogen and the hydrides were characterized by high-resolution scanning electron microscope (SEM) and scanning transmission electron microscope (STEM). The results revealed that the presence of solute hydrogen reduced the critical resolved shear stress (CRSS) for prismatic slip and enhanced the formation of stacking faults. Conversely, hydride formation in the micropillars increased the yield stress, followed by strain hardening due to strain incompatibility. Slip transmission across the hydride phase occurred upon increasing plastic slip, ultimately leading to a brittle failure.