Compositionally graded joints between magnetically dissimilar alloys achieved through directed energy deposition

S Firdosy and N Ury and AB Kustas and JD Carroll and P Pathare and Z Casias and D Tung and D Susan and NS Bobbitt and M Chandross and JP Borgonia and VA Ravi and RP Dillon, SCRIPTA MATERIALIA, 202, 114005 (2021).

DOI: 10.1016/j.scriptamat.2021.114005

Compositionally graded cylinders comprising FeCo-2V, a soft magnetic alloy, and 316L stainless steel, were produced by directed energy deposition incorporating two different gradient lengths. Five distinct regions in the microstructure were observed in both the as-printed and annealed gradients. When normalized for the gradient length, the gradients showed similar grain size and microhardness profiles. In tensile tests, the as-printed samples failed in the 316L region with an effective total "composite" strain of 20-30% and overall strength approaching that of wrought 316L. The annealed samples failed in the FeCo-2V region. Neither exhibited failure in the gradient region. Molecular dynamics simulations were used to calculate tensile strength as a function of composition, showing good correlation to experimental trends but not absolute values. This work demonstrates the tunability of site-specific properties using blown powder directed energy deposition to gradually grade from FeCo-2V to 316L stainless steel in a monolithic component. (c) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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