The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: To find an additive manufacturing process/method to produce large scale components for military systems that have repeatable material properties, using a physics-based approach. DESCRIPTION: Additive manufacturing (AM) is currently and will continue to be a major area of interest for the Army moving forward. This is for a variety of reasons, including sustainment (printing obsolete or difficult to acquire parts, part repair), readiness (eliminating long lead times), light-weighting (geometry optimization), and more. The Army, more so than most other industries, has the need to additively manufacture large scale metallic components. There are several AM methods that can be used for this (powder bed, electron beam, WAAM, cold spray, etc.), but none that are widely accepted (within the Army) to producing large scale (larger than 1 m2 in the x-y plane) production parts. GVSC Materials Directorate wishes to partner through the STTR program to further characterize large scale metal AM parts and work toward certification of the parts and the AM process/method used to manufacture them. Successful applicants must have commercially available AM technology (one AM method) that can print steel, aluminum, and/or titanium alloys, and meets a minimum build size of 1 square meter (in the x-y plane). Applicants must also have a planned or currently available in-situ process/technology that uses a physics-based approach to ensure repeatability and statistical confidence of material properties of the parts produced, regardless of the part geometry. Awardees will partner with a research entity which will test printed material in two phases. The intent of Phase I is for each awardee to use a different, large scale AM method. Phase I will consist of material characterization testing that will include, at a minimum; tensile properties, hardness distribution, impact toughness (Charpy v-notch or as-appropriate), microstructural analysis, void fraction, and fatigue. After Phase I, the awardees/AM methods will be down-selected to the one (or two) that show the most promising results and move forward into Phase II. Phase II will consist of refining the physics-based process to increase, as much as possible, the repeatability of material properties of parts with differing geometries. Material characterization testing will continue by taking samples directly from printed parts (vehicle components), which are identified by the government. The effort in Phase II is to increase the baseline properties identified in the first set of tests, resulting in a process and parts that meet Army weapon systems requirements. The final deliverables will be one or more prototype parts that can be used for on-vehicle testing, and a physics-based record showing the repeatability of the specific AM process. PHASE I: Phase I is intended for each awardee to use a different, large scale AM method (powder bed, electron beam, WAAM, cold spray, etc.). Phase I will determine the AM method(s)/process(es) that have the greatest feasibility to produce repeatable and statistically confident material properties of large scale metallic parts. Phase I will consist of material characterization testing that will include, at a minimum; tensile properties, hardness distribution, impact toughness (Charpy v-notch or as-appropriate), microstructural analysis, void fraction, and fatigue. PHASE II: Phase II awards will be made to firms on the basis of results of their Phase I effort and potential to transition to Phase III. Phase II will consist of refining the physics-based process to increase, as much as possible, the repeatability of material properties of parts with differing geometries. Material characterization testing will continue by taking samples directly from printed parts, which are identified by the government. The effort in Phase II is to increase the baseline properties identified in the first set of tests, resulting in a process and parts that meet Army weapon systems requirements. The final deliverable will be one or more prototype parts that can be used for on-vehicle testing. PHASE III DUAL USE APPLICATIONS: Phase III will end with a commercially available Additive Manufacturing method, with a physics-based control process, that is capable of printing large scale metallic components with reliable and repeatable material properties. The technology can be used to produce large components for Army vehicles such as structural components, chassis components, large turret components, large hatches, etc. It will also be useful for other industries, such as aerospace, large truck/trailer, and others. REFERENCES: 1. Gordon, Jerard & Narra, Sneha & Cunningham, Ross & Liu, He & Chen, Hangman & Suter, Robert & Beuth, Jack & Rollett, Anthony. (2020). Defect structure process maps for laser powder bed fusion additive manufacturing. Additive Manufacturing. 101552. 10.1016/j.addma.2020.101552; 2. Promoppatum, Patcharapit & Rollett, Anthony. (2020). Influence of material constitutive models on thermomechanical behaviors in the laser powder bed fusion of Ti-6Al-4V. Additive Manufacturing. 10.1016/j.addma.2020.101680; 3. https://www.sbir.gov/content/predictive-modeling-tools-metal-based-additive-manufacturing-1 KEYWORDS: additive manufacturing, big metal, electron beam, EBAM, wire arc, WAAM, cold spray, powder bed, physics-based control, in-situ control process, sustainment, readiness, lightweighting
