Texture development in friction stir welds

Abstract

The shear textures that develop in friction stir welds are reviewed and discussed. In all the materials examined, including face centred cubic (fcc), body centred cubic (bcc) and hexagonal close-packed (hcp) materials, friction stir welding produces a predominant shear texture with the close-packed directions aligned with the shear direction (SD) and the close-packed plane normal perpendicular to both the SD and the shear plane normal. This orientation corresponds to the B/ ideal shear texture in fcc materials, the D₁ ideal shear texture in bcc materials, and the P₁ ideal shear texture in hcp titanium alloys. Titanium friction stir welds fabricated above the β transus temperature can contain evidence of ideal shear texture components from both the bcc D₁ (after transformation to the hcp phase according to the Burgers orientation relationship) and the hcp P₁ shear textures. Thus, similar shear textures develop in friction stir welds of fcc, bcc and hcp materials.