Investigation of microstructure-tensile behavior relationship in Hastelloy X Ni-based superalloy processed by laser powder-bed fusion: Insights into the elevated temperature ductility loss

The microstructure-tensile response correlation in a crack-free laser powder-bed fusion (LPBF) Hastelloy X Nibased superalloy is investigated. The LPBF process parameters in terms of volumetric energy density were optimized to obtain the maximum relative densities, as well as the lowest defect size. The microstructure and tensile behavior of samples were evaluated. Microstructural characterizations showed that the columnar grains of the austenite phase consisted of a submicron cellular microstructure with a weak texture along 100 110 parallel to the building direction orientation, resulted in the stress concentration in the grain boundaries, leading to inferior elevated temperature tensile properties.