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Author ORCID Identifier

Nadia Kouraytem

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Springer New York LLC

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Nearly all energy technologies utilize heat exchangers and recuperators within the power cycle. To further improve the cost-effectiveness of recuperators, costly high temperature Inconel 625 superalloy was substituted with a more affordable Stainless Steel 316L to be used at the low-temperature side of the heat exchanger. Bimetallic samples for analysis and examination were fabricated by combining Laser Powder-bed Fusion and Directed Energy Deposition. Two transition strategies for joining to the laser powder-bed fusion steel were explored, namely, a direct transition and an intermediate layer of 50% nickel powder mixed with 50% steel powder through Directed Energy Deposition. The microstructure and chemical composition of the multi-material structures were compared to the single alloy counterparts. Iron rich regions within the 50/50 transition zone suggest elemental segregation during the deposition of the 50/50 mixed zone. Vickers hardness values measured using micro-indentation are presented across both types of transitions and show a relative lower value in the 50/50 mixed zone.

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