Wear and corrosion performance of textured Hastelloy-X fabricated by laser powder bed fusion: Process window and microstructural features

Abstract

This study investigated the effect of volumetric energy density (VED) on the densification and microstructural evolution of Hastelloy-X (HX) alloy fabricated by the laser powder bed fusion (L-PBF) process, and how these changes affect wear and corrosion performance. Variations in VED altered melt pool geometries, which influenced densification. In addition, VED also affected the growth direction of cellular microstructures, resulting in different crystallographic texture development. Specifically, high VED showed the lowest densification with strong alignment in x,y, and z directions. Meanwhile, medium VED exhibited the highest densification with a mixed and crystallographic texture along the building direction, while low VED led to moderate densification with weak alignment overall. The wear and corrosion properties of the samples varied with their densification and microstructural characteristics. In terms of wear mechanisms, a distinct load dependence was observed. Oxidative wear dominated at low loads, where the strong (100)-oriented crystallographic texture promoted oxide stability and improved the wear resistance. While deformation wear prevailed at higher loads, where hardness became the determining factor. As for corrosion resistance, higher densification, grain refinement, and high dislocation density generally facilitated passive film formation and improved resistance. However, crystallographic texture should also be considered, since (100)-oriented regions are more prone to corrosion than other orientations, indicating that the crystallographic texture inherent to L-PBF processing is an important factor in corrosion behavior. The results demonstrate that optimizing L-PBF process parameters is essential for tailoring microstructure and improving the wear and corrosion resistance of Ni-based superalloys.