Texture evolution in nanocrystalline Ta under shock compression

摘要

We present systematic investigation on texture evolution in nanocrystalline Ta under planar shock wave loading at different impact velocities. Seven representative initial textures and two loading directions are studied via large-scale molecular dynamics simulations. Orientation mapping and texture analysis, including orientation distribution functions, pole figures, and inverse pole figures, are performed. Shock compression induces a 〈221〉 texture in nanocrystalline Ta initially with no texture,〈100〉 fiber texture, {100}〈100〉 texture, and θ + γ rolling texture via twinning, which can be traced back to grains initially with 〈100〉. A 〈100〉 texture is induced via twinning for nanocrystalline Ta initially with no texture, 〈110〉 fiber texture, and α + γ rolling texture and can be traced back to 〈110〉. Dislocation slip and grain boundary sliding lead to the movement of 〈110〉 toward〈111〉, and the strengthening of 〈100〉 and〈111〉 orientation densities. The generation of new textures is observed for most cases. However, no new texture is found in the 〈111〉 fiber texture case for shock loading parallel to the fiber, and a much slower elastic-plastic transition occurs due to the lack of deformation twinning.