Hot Tensile Deformation and Fracture Behavior of Wire Arc Additive Manufactured Hastelloy C-276

In this study, a thin-walled plate of nickel-based superalloy Hastelloy C-276 was fabricated via wire arc additive manufacturing (WAAM) technology. The microstructural characteristics and tensile properties of the as-built specimens at elevated temperatures were evaluated. Typical austenitic microstructure was noticed with equiaxed and elongated columnar dendrites along the building direction. Intermetallic p phases rich in Mo were confirmed from energy dispersive X-ray spectroscopy (EDS) microanalysis along the grain boundaries and interdendritic regions. The tensile results of as-deposited samples from different directions revealed lower anisotropy at ambient and elevated temperatures. The degree of plastic deformation was higher at elevated temperatures and is in line with the percent of elongation values. Digital image correlation (DIC) was used to evaluate the localized strain distribution. Hardness measurements showed a negligible variation along the building direction due to uniform directional dendrites and were in the range of 212–232 HV. All the tensile samples fractured in ductile mode, while intergranular cracks and intermetallic phases were noticed at elevated temperatures. These outcomes suggest that WAAM processed Hastelloy C-276 is a suitable structural material for elevated temperature applications up to 800 ºC.