H effect on the plasticity of Ti575 alloy

Adsorption of hydrogen (H) can result in severe performance degradation of Ti alloys. In this study, the effect of H on the plasticity of Ti-5Al-7 5V-0.5Si (Ti575) alloy is investigated. High resolution digital image correlation (HRDIC) is employed to elucidate the effect of H on the strain distribution and dislocation slip character of the alloy during mechanical loading. It is found that H enhances slip heterogeneity and promotes the formation of long and sparse prismatic slip bands in the α phase, which can extend to across several grains. Such heterogenous prismatic slip bands are likely to originate from the lenticular hydrides, which have the prismatic plane as their habit plane. In addition, H also shows considerable effect on the plasticity of β phase, which facilitates the slip transmission and enhances the slip localisation.