LAUSR

Abstract In the present study, solid solution strengthened Ni-based superalloy Hastelloy X (HX) parts were fabricated using the laser powder bed fusion (LPBF) additive manufacturing process with the intent of developing a strong crystallographic texture. Their tensile properties at room temperature were investigated along the , , and crystallographic orientations. Tensile behavior was found to be highly dependent on the crystallographic orientation and present unique combinations of strength and ductility when compared with other LPBF-HX counterparts. EBSD (Electron backscatter diffraction) analysis after fracture revealed deformation twinning in the and samples, but not in the orientation. It was observed that crystallographic orientation had a great impact on the effective stacking fault energies. Critical stress for deformation twinning was also observed to be crystallographic orientation-dependent. It was close, if not below the yield strength (YS) for and , while it was well above the ultimate tensile strength (UTS) of the orientation. The YS value of (807 ± 28 MPa) was higher than that of (693 ± 8 MPa) and (648 ± 13 MPa). The results suggest that deformation twinning can occur in solid solution strengthened Ni-base superalloys at room temperature, and their formation does not mandatorily require the presence of γ′ precipitates or thermally assisted mechanisms. In contrast to the and orientations, rotation of the lattice after deformation was found for the .