Keyhole TIG welding of newly developed nickel-based superalloy VDM Alloy 780

Abstract The influence of keyhole TIG (K-TIG) welding parameters on the weld geometry and defects a new nickel-based superalloy VDM Alloy 780 alloy were investigated using statistical design experiment, microstructures heat-affected zone (HAZ) fusion (FZ) K-TIG-welded characterized. No cracks are found in FZ HAZ. Travel speed significantly influences minimum width (Wm), face root excess metal, underfill, average pore diameter. Welding current interaction current*travel metals, respectively. Interdendritic microconstituents identified as (Nb,Ti)C particles γ/Laves eutectic constituents based SEM–EDS analysis. In addition, plate-like precipitates likely to be δ/η phase observed surrounding interdendritic Laves eutectics, γ′ inhomogeneously precipitated FZ. partially melted (PMZ), (Nb,Ti)C, phase, liquated resolidified regions. Constitutional liquation HAZ is where appears associated with product.