Multi-dimensional morphology of hydride diffusion layer and associated sequential twinning in commercial pure titanium

The dominant hydride precipitates have been well demonstrated to follow two types of orientation relationships (ORs) with Ti matrix: OR1 {0001}//{001}, <12¯10>//<110> and OR2 {0001}//{11¯1}, <12¯10>//<110>. Within the grains special orientations, complicated interactions different variants inside Ti-hydride diffusion layer are characterized in this work. For layer, orientations {101¯0} plane parallel sample surface a-axis normal direction prefer multiple variants. favorable for are: {101¯3} corresponding one variant dominated c-axis preferred. Furthermore, {101¯2} extension twins {112¯2} contraction activated accommodate hydride-induced expansion local misfit strain. stimulation these is also orientation-dependent: observed deviated from normal, respectively. further selection each twin mode performed through shear accommodation hydride-twin pairs.