High Performance Nuclear Materials Additive Manufacturing with Integrated Thermal Processing

Additive manufacturing can enable materials with enhanced performance and facilitate rapid development cycles relative to conventional processing. These 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 novel integrated additive manufacturing thermal processing 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 testing showed feasibility of the process on directed energy deposition printed walls using modified 9Cr-1Mo steels, a commercially available AM-relevant nuclear alloy. Mechanical testing demonstrated increases in part ductility and homogeneity for integrated thermal processing relative to baseline samples. Phase II tasks will involve continued process development, in-depth characterization, and creep testing. In addition, larger scale prototypes will be printed on an industrial wire arc additive manufacturing machine with project partners and destructively evaluated. Publications and outreach to the nuclear materials, advanced manufacturing and conventional power generation communities will assist with technology transfer and commercialization. Commercial Applications and Other Benefits: Integrated processing holds potential for expanded design opportunities in new fabrication and repair work for high performance microstructures. In-situ thermal processing could offer a pathway to large and complex components, circumventing the need for difficult, costly, and time consuming post-build thermal processing. Summary for Members of Congress Nuclear materials must withstand extremes of stress, radiation, and temperature; additive manufacturing can create complex parts with reduced development cycles. This project will develop innovative integrated additive manufacturing and thermal processing methods which can enhance material performance and properties.