Characterisation of residual stresses in dissimilar friction stir welded aluminium and copper

In the present work, dissimilar friction stir welding of aluminium alloy 5754 and C11000 copper plates were carried out and the residual stresses were characterised. Hole drilling technique was employed to measure the residual stress at various directions. The dissimilar joints were produced by varying the major process parameters such as tool rotational speed and traverse speed. A heterogeneous microstructure consisting of intercalation of both the materials was observed in the weld zone. The measurements indicated that the distribution of the residual stress along the thickness of the welded plates was not uniform. The nature of the residual stress was compressive in most of the joints. The influence of tool rotational speed and traverse speed on the distribution of residual stress was further reported.