Office of Naval Research (ONR) Additive Manufacturing Alloys for Naval Environments (AMANE)

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Overview: The Office of Naval Research (ONR) is interested in receiving proposals for Additive Manufacturing Alloys for Naval Environments (AMANE). The objective of this research opportunity is to design, develop and optimize new metallic alloy compositions for additive manufacturing (AM) that are resistant to the effects of the Naval/maritime environment. This program shall use a fundamental Integrated Computational Materials Engineering (ICME) framework coupled with experimentation to relate variations in alloy chemistry, AM processing parameters, and post-processing conditions to the mechanical and electrochemical/corrosion properties that can be achieved. Participants will use this knowledge to identify an alloy composition range optimized to fabricate robust AM components that is resistant to the effects of exposure in a maritime environment. Background: Additive Manufacturing (AM) is attracting considerable recent attention for its ability to fabricate complex components in limited lot sizes. While there are many AM technologies, they all share the ability to build, from a 3D Computer Aided Design (CAD) model, a physical 3D component through a layer-by-layer deposition of material. Recent advances in computational power, reliability, AM part quality, and available AM materials and systems have all contributed to the increased capabilities of this technique. One aspect of particular interest is the ability to fabricate AM components from structural metals. With the recent growth of additive manufacturing, there has been a corresponding increase in the number of materials specifically developed for this technology. The feedstock compositions for metallic AM often differ from the conventional alloy compositions in order to achieve the desired chemistry and properties after fabrication. Thus, AM feedstock suppliers have developed equivalent compositions for many common alloys, including stainless steel, titanium, and inconel. Such alloy equivalents do not exist for many Naval-specific alloys; AM of these potential Naval applications is precluded by the lack of corrosion-resistant or environmentally-stable alloy compositions optimized for the AM process. Program Objectives: The objective of this program is to design, develop and optimize new metallic alloy compositions for AM that are resistant to the effects of the Naval/maritime environment. This program shall develop and/or apply computational models and tools to identify potential alloy compositions appropriate for the thermal and stress conditions inherent in the AM process and identify the effects of alloy chemistry, AM processing parameters, and post-processing conditions on the phases and precipitate distributions that will evolve during fabrication and post-processing, and predict the strength and corrosion potential of the resultant material. These calculations must be coupled with experimental validation of the model predictions as a function of alloy chemistry, deposition parameters, and post-processing conditions to identify an optimized alloy composition and processing window to achieve the strength and corrosion performance needed for that alloy. In addition, this program will reveal any differences between conventional materials and their corresponding AM material equivalents in mechanical properties, stability and resistance to environmental effects. While the primary focus of this program is on the development of new, environmentally-stable materials for AM applications, worthy proposals related to other Naval-unique topics in AM will also be considered, such as new AM alloys that do not require post-processing to achieve acceptable properties in expeditionary manufacturing. The ultimate focus of this program will be on powder bed fusion (PBF) AM technologies, although other fabrication methods may be considered during alloy development. The respondent is encouraged to link their proposal to a specific Navy application/alloy need and describe the expected benefits of additively manufacturing that component, as well as other Naval structures, from this alloy. Additional consideration will be given for alloy compositions within current DoD-qualified/approved alloy composition windows. In summary, the proposed research for AMANE seeks to: • Understand the effects of variations in alloy chemistry, AM processing parameters, and post-processing conditions on the resultant mechanical and electrochemical/corrosion properties. • Apply an ICME methodology coupled with experimentation to identify a new metallic alloy composition window for additive manufacturing that can satisfy or exceed the strength and corrosion property requirements of the corresponding conventional Naval alloys. • Develop and optimize the alloy chemistry, AM processing parameters, and post-processing conditions to achieve the strength and corrosion resistance targets. • Determine the differences in mechanical properties, stability, and resistance to environmental effects between the new AM material developed in this program and the corresponding conventional alloy.

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