Effect of rotation speed on texture type in friction stir welding joint for 6082-T6 aluminum alloy

The evolutions of grain morphology, grain boundary features and texture components on the upper surface of friction stir welding nugget for 6082-T6 aluminum alloy at different rotation speeds of tool were studied by electron backscatter diffraction technology combined with orientation analysis software. The results indicated that the (110) [001] Goss texture and (114)[$22 {\bar 1}$] texture were formed in the nugget zone under the shear stress introduced by the pin, and the upsetting pressure of the shoulder made it rotate to certain angle along the transverse direction, leading to the formation of (112)[11${\bar 1}$] copper texture. With elevating the rotation speed of tool, the rotation angle of grains along the transverse direction increased, resulting in the further formation of (100) [011] shear texture and (11${\bar 1}$)[112] texture. [110] fiber texture was formed by extrusion of grain in nugget zone by pin. When the rotation speed of tool was elevated from 1 200 to 2 000 r/min, the extrusion degree was increased, which resulted in a significant increase in the components of [110] fiber texture.