b'Additive ManufacturingA multi-wire, arc-based, metal additive manufacturing system rapidly of Multi-functional,builds functionally graded components for harsh environments.Large-scale Components F unctionally graded components offer the potential to address materials requirements in harsh environments on a local scale and eliminate the need to develop a metallic alloy that satisfies all design requirements, such as physical property requirements like high temperature structural strength, thermal conductivity, etc., as well as environmental resistance criteria. Researchers developed an additive manufacturing system that can deposit controlled compositions on a local scale during component fabrication. The multi-wire arc additive manufacturing PROJECT NUMBER:system can deliver up to three different welding wires into the weld pool to control 20A44-113 the local alloy composition, effectively placing optimum alloy compositions where TOTAL APPROVED AMOUNT:they are needed in a component. For example, a component could be manufacturing $796,500 over 3 years with corrosion resistant alloy internally with high strength structural alloys on the outside. Because the system is based on arc welding, high deposition rates PRINCIPAL INVESTIGATOR:(approximately 10-100 times that of powder-based three-dimensional metal Thomas Lillo printing) and high material utilization efficiency (near 100% for multi-wire arc CO-INVESTIGATORS: additive manufacturing versus approximately 40-60% for powder-based three-Eric Larsen, INL dimensional metal printing) can be achieved.Jason Walleser, INL Researchers demonstrated that deposits could be continuously graded from one Michael Glazoff, INL end of the build to the other. Simple walls were fabricated that were graded Nathan Huft, INLfrom a high temperature nickel-based structural alloy, Hastelloy N, to pure nickel, Denis Clark, DEClark Weldingwhich is highly resistant to molten salts but lacks any significant high temperature Engineering, PLLC structural strength. Furthermore, it was demonstrated that the characteristics of the composition gradient in layer-by-layer builds could be influenced by deposition parameters, such as heat input, ranging from a stepped profile at low heat input to an almost continuous gradient at higher heat inputs due to the extent of dilution from the underlying layer as influenced by heat input. Finally, it was demonstrated that design of the proper composition gradient in conjunction with a proper post-build heat treatment could produce a gradient in microstructure and properties in simple iron-based builds. The influence of these graded microstructures on shock wave propagation was quantified using dynamic compression tests using the split Hopkins pressure bar system.This project just scratches the surface of what is possible with multi-wire arc additive manufacturing and starts to elucidate the influence of the numerous operating parameters. Also, some of the design considerations and issues associated with building large functionally graded components are now evident. However, the advantages of multi-wire arc additive manufacturing in joining dissimilar metals and applying corrosion resistant claddings to high temperature structural metals are immediately clear from the research results.82'