Deformation twinning-induced texture evolution in Ti under shock compression: An atomistic simulation study

Abstract

Shock-induced texture evolution in polycrystalline titanium (Ti) with different initial textures under different impact velocities is investigated systematically via large-scale molecular dynamics simulations. {101¯2}⟨101¯1⟩, {101¯1}⟨101¯2⟩, and {112¯1}⟨112¯6¯⟩ deformation twinning are observed upon shock compression; however, the texture evolution is mainly attributed to {101¯2} and {101¯1} twinning based on resolved shear stress analysis and orientation mapping. When a single-step texture change occurs in the loading configuration, the {101¯1} twinning dominates, whereas when a two-step texture change occurs in the loading configuration, the {101¯2} twinning prevails: a new texture is initially induced via the {101¯2} twinning, followed by the formation of another texture component through the {101¯1} twinning, except for the loading configuration initially with no texture. The twinning dislocations of {112¯1} twins comprise both an edge component and a screw component. The {101¯2} and {101¯1} twinning occur via the HCPmatrix to BCC to HCPtwin phase transformation sequence, induced solely by atomic shuffles without shear deformation. The HCP phase and the transient BCC phase obey the Pitsch–Schrader orientation relationship. Different twinning relationships can be achieved by different variants during phase transformation.