Influence of Linear Friction Welding parameters on the residual stress development in Ti-6246

Linear Friction Welding (LFW) is a novel welding technology, which utilises a combination of frictional heating and plastic deformation to join difficult-to-weld materials. However, when joining high temperature materials large residual stresses are generated, which can be detrimental to the joint performance. In this work, the residual stress development due to LFW in β-forged Ti-6246 aerospace alloy was investigated using energy dispersive X-ray diffraction, at the European Synchrotron Radiation Facility in Grenoble, France, focusing on the influence of the consolidation pressure on the stress development. As Ti-6246 is a two-phase alloy, calculating the stresses in the alloy required the characterisation of strain in both phases separately. For accurate strain measurements, additional measurements of the stress-free lattice spacing as a function of position across the weld line were carried out using a laboratory based x-ray source in combination with the biaxial sin ²ψ approach. The advantages and limitations of this technique, with respect to resolution and accuracy, are highlighted and discussed.