Advanced or additive manufacturing (AM) can enable materials with enhanced performance and facilitate rapid development cycles relative to conventional processes. Hence, AM process improvements can benefit nuclear energy materials which are subject to high thermal flux, intense irradiation fields, high stresses, and be exposed to reactive fluids and gases. This project will develop and demonstrate novel integrated AM thermal processing methods relevant to high performance nuclear energy alloys. A major focus of this work is to improve the microstructure, uniformity, and toughness of as-printed components without subjecting the part to a separate post process heat treatment, which is associated with risks of distortion and cracking. Phase I R&D tasks will involve detailed process studies on modified 9Cr-1Mo steels, a commercially available AM-relevant nuclear alloy. A metal 3D printing wire-arc directed energy deposition testbed will be integrated with in-situ thermal processing equipment. Baseline and integrated AM thermal processing specimens will undergo mechanical testing and advanced characterization. Feasibility studies will determine suitability of implementing the processing on various AM processes, materials, and component geometries. Outreach efforts are planned with the nuclear materials and AM communities for validation, and to establish prototyping and development partnerships, along with creating a detailed plan for Phase II demonstrations on an expanded list of nuclear-relevant materials. Commercial Applications and Other
Benefits: integrated processing holds potential for expanded process capability, as many candidate high performance AM materials experience cracking and/or residual stresses limiting functional use. Additionally, in-situ thermal processing could offer a pathway to large and complex components, circumventing the need for post-build thermal processing which can be costly, distortion-inducing, time and energy consuming, or simply not feasible.
