Grain size and misorientation evolution in linear friction welding of additively manufactured IN718 to forged superalloy AD730™

Selective Laser Melted (SLM) Inconel718 (IN718) superalloy was linear friction welded (LFWed) to forged AD730™ Nickel-based superalloy. Successful joints free of micro-porosity, micro-cracking, and oxides were obtained. Microstructure variations across the weld line developed during LFW examined using different techniques, including laser confocal microscopy, scanning electron energy dispersive spectroscopy (EDS) backscatter diffraction (EBSD). The microstructure also evaluated, particularly in terms Grain size misorientation changes determined correlated with microhardness evolution regions joint. characteristics on both sides joint analyzed related deformation temperature paths imposed process. Dynamic recrystallization (DRX) occurred dissimilar it found that Discontinuous DRX (DDRX) Continuous (CDRX) took place WZ TMAZ, respectively. In order study influence starting experiments, a homogenized SLM IN718 sample compared non-homogenized sample. A clear change grain levels heat thermomechanical affected zones observed between two conditions. differences greater degree strain induced increasing effect solid solution strengthening mechanism caused by partial dissolution second-phase particles matrix.