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There are abundant studies on additive manufacturing of Ni alloys, such as Inconel 718. However, the studies on the microstructure and the deformation behavior of solid solution strengthened Ni alloys, such as Haynes 230, are limited. Here we compare the microstructure and the mechanical behavior of as-printed and stress-relieved Haynes 230 Ni alloys prepared by laser powder bed fusion. Transmission electron microscopy analysis revealed M₂₃C₆ carbides decorated at the dislocation cell walls in the as-printed material transformed to well-aligned arrays of M₆C nanoprecipitates separated by an array spacing of 500 nm after stress-relief (heat treatment). The nanoprecipitates in stress-relieved alloy have formed numerous aligned orientation relationships with the matrix despite their large lattice mismatch. Post-tension microscopy analyses demonstrated high-density dislocation networks in the as-printed …