On the interplay of internal voids, mechanical properties, and residual stresses in additively manufactured Haynes 282

Complex geometries and topology optimisations for weight and materials savings are leading drivers for the additive manufacturing of Ni-based superalloys through electron beam powder bed fusion (PBF-EB). However, there is a marked departure in these geometrically complex components with respect to the thermal signatures understood in commonly studied prismatic PBF-EB test coupons. This often results in unaccounted site-specific microstructure-property variations in complex PBF-EB builds. Here, the effects of topological changes, such as intentionally engineered internal voids, on the mechanical performance of an as-fabricated Haynes 282 monolith is revealed. The internal voids serve as representative physical models for changing thermal boundary conditions with build height. Complementary local nanoindentations, multi-scale microscopy, and residual stress measurements were used to understand the mechanisms behind geometry-structure-property relationships. The results highlight the effectiveness and influence of changing thermal conditions on the local mechanical property response of PBF-EB Haynes 282.