Effect of tool position on the fatigue properties of dissimilar 2024-7075 sheets joined by friction stir welding

The fatigue strength of welded joints represents the core problem for their industrial applications. Friction stir welding (FSW) demonstrated the enhancement of fatigue resistance for aluminium and magnesium alloys, with respect to traditional fusion techniques. In addition, the possibility to join dissimilar alloys representing an important aspect for such technology as well as the reduction of residual stresses and apparent necessity to avoid heavy heat treatments are also positive factors. In this paper, the results about the fatigue properties and the fatigue crack growth behaviour of dissimilar 2024-7075 jointed aluminium sheets are presented for FSW butt welds, produced with different positions of the tool with respect to the weld line.