| Friction welding is a solid state joining process and can be used to successfully join similar and dissimilar Ni-based superalloy base materials. The objective of this project involves the optimization of welding parameters and post weld heat treatment procedures during similar Ni-base wrought alloy and dissimilar (Ni-base wrought alloy/Ni-base cast alloy) friction welding. Extensive microstructural analysis was carried using a combination of optical, scanning electron microscopy, transmission electron microscopy and atomic force microscopy. The application of a [re-solution + stabilization + precipitation] post weld treatment procedure produced the optimum balance of joint tensile strength and ductility properties in Ni-base wrought alloy friction joints. TEM analysis provided an insight concerning the various mechanisms that occur in friction welded joints, particularly with regard to changes in precipitate chemistry and in particle distributions. |
