Additive Manufacturing

Naval Nuclear Laboratory is seeking innovative methods to bridge gaps and accelerate implementation of additive manufacturing (AM) processes. 1) Materials processed by AM methods yield a range of microstructures depending on the fabrication process used and variability in parameters such as power input and cooling rate. Microstructures are typically different than traditional wrought or weld metals. Models to predict microstructures and link to material properties are not yet mature. o Innovative methods to improve comprehensive and quantitative understanding of the factors affecting recrystallization and translation of those items into predictive modeling are sought. 2) Additive manufacturing of graded metallic structures for tailored surface properties is not routine, and printing of composites such as ceramic and metal interspersed in the same structure is not a mature technology. Advances in the ability to print composites, such as ceramic and metal, in the same structure are needed to take full advantage of AM technology in a wide range of applications. o Technology innovations are being sought in the area of printing composite components. 3) Post-build inspection of parts made by laser-powder bed fusion (L-PBF) is challenging due to probe access and complex geometry. Reliable in-situ inspection methods coupled with data analysis methods (e.g., machine learning) are required to consistently detect issues during builds as part of a modern quality assurance system. Ideally, these methods should be coupled with the ability to perform repairs during builds. Non-destructive evaluation methods are not yet widely available and optimized for additively manufactured parts. o An integrated quality assurance plan combining in-situ and post-build inspection techniques is being sought. 4) AM equipment and processes today require knowledgeable operators and engineers to be highly involved in the process to ensure consistent production of high quality builds. The ability to enable 'print on demand' at facilities where AM is not their primary business - such as shipyards who specialize in maintenance and construction or vendors that specialize in integrating components into systems - is needed to make this technology more useful to the Navy. o Innovations are being sought that enable more repeatable builds and more reliable first time builds to support AM at the point of need. 5) Surfaces of L-BPF manufactured parts are rough due to the nature of the process, limiting application in rotating equipment and other high fatigue-cycle environments. o Methods are being sought that allow fatigue lifetimes similar to machined surfaces with less and faster post-processing of this technology. 6) Wire-based AM methods produce near-net parts that must be machined to final shape but can fabricate large components quickly without need for tooling. However, heat buildup during wire-based AM causes distortion, residual stress, degraded properties and inspect-ability in some materials due to less-than-optimal cooling rates which lead to coarse and anisotropic microstructures. o Innovations are needed that improve thermal/mechanical control and controlled cooling during builds to harness this technology for widespread NNL application. 7) While AM is inherently a digital fabrication technology, the full 'system' of development and operation including use of 3D models, maintaining cybersecurity while sharing files across physical sites, printing, integrating embedded and/or printed sensors, efficient post-processing, and generating a digital twin has yet to be developed in a convenient format for end users. Tying this effort to artificial intelligence methods that evaluate sensor data to enable condition-based maintenance would enable an integrated, modern manufacturing and operations system. o Innovations are being sought in the development of an integrated, modern manufacturing and operations system. 8) Carbon steels, high strength shipbuilding steels, and pressure vessel steels are of interest for Navy applications. However, conventional sources of material (forgings, castings) can be time intensive to procure. AM methods produce complex shapes that lead to enhanced, tailored structural or thermal performance. Processing size limits, surface roughness, and unknown structural performance of AM parts in similar applications restrict the usefulness of applying these technologies to large components. o Innovative solutions to these limitations are needed for widespread adoption in the nuclear industry and shipbuilding applications. Pre-Proposal Conference: Question & Answer Session A pre-proposal conference will be conducted to discuss the proposed work area and answer any questions with respect to the project on: - May 19, 2022, at 3:00 - 4:00 pm EST Contact Anne Roth to sign up to attend the Pre-Proposal Conference (Q&A session).