Friction stir processing and characterisation of A380 cast aluminium alloy

The surfaces of cast A380 aluminium alloy plates were modified by friction stir processing. A milling machine was utilised with a tool rotating at 1400 rev min(-1) and traversing at a rate of 16 mm min(-1). The 400 mu m(-2) mm processed layers were obtained on the surfaces of the cast aluminium sheets. It was seen from the optical microscope examinations that the Si particles were homogeneously distributed in the Al matrix. The hardness of the cast aluminium sheets increased from 60 to 90 HB10 after friction stir processing. Samples were subjected to wear tests with 6 mm diameter alumina balls in dry condition. Wear tracks were examined by scanning electron microscope and profilometer. Wear rate of surface modified aluminium sheets were found to be 50% lower than the ones without surface modification.