The aim of the present work was to study the possibility of joining two dissimilar cast Al–Si alloys, typically, A319 and A413 using friction stir welding. Both of the mechanical and microstructural characteristics of dissimilar A319 and A413 cast aluminum friction stir welded joints were studied. The effect of both tool rotational and welding speeds on the mechanical and microstructural characteristics was investigated. The results showed that sound joints between the A319 and A413 plates were successfully obtained. The average size of the Si particles increases with increasing the tool rotational speed and/or decreasing the welding speed. The average size of α-Al grains increases with increasing the tool rotational speed and/or decreasing the welding speed. At the center of stirred zone, the Si particles were found to be uniformly distributed at low welding or high rotational speeds in comparison with at higher welding or lower rotational speeds. The hardness of the welded region was higher than the hardness range of A413 base alloy, but it is approximately located within the hardness range of A319 base alloy. The average hardness of the welded regions increases with increasing the welding speed and/or reducing the tool rotational speed. The tensile tests results showed that the welded joints have better tensile properties than the base alloys. All of the tensile specimens were fractured outside the welded regions at the A413 base metal placed at the advancing side. |
