Aluminum-Scandium Substructure for Thermal Protection Systems

Compatible aluminum substructure is important for Thermal Protection Systems (TPS). Aluminum-scandium alloy has advantages of performance, producibility, affordability and scalability for use as substructure. A commercially available aluminum-scandium alloy is available as a standard feedstock for wire arc-DED additive manufacturing. Material produced with this wire provides processing and performance advantages over other aluminum additive manufactured materials. The wire, called Alloy 5025, is produced by Hobart Brothers, one of the largest US based aluminum welding wire manufacturers. Big Metal Additive has been working in partnership with Hobart Brothers to introduce this material to Defense customers for additive manufactured solutions. It has been proposed to several defense prime contractors for production of prototypes, replacement parts and first articles of new designs intended for rate production. Customers have a difficult time embracing this new material. There is not yet enough compelling data for customers to select Alloy 5025 over other aluminum alloy wire feedstock materials. Customers need to see a full dataset for thick wall and thin wall test elements. The dataset must include testing of a large sample size and critical mechanical and physical properties. Inspection results must also be provided which demonstrate effectiveness of surface NDE (non-destructive evaluation) and volumetric NDE. BMA has produced preliminary samples of Alloy 5025 for mechanical testing. Samples were heat treated with a simple aging anneal recommended by Hobart Bros. and tensile data was collected. The preliminary data shows a tensile yield strength of 38 ksi, tensile ultimate strength of 48 ksi and 8% elongation. We believe that with an optimized heat treatment we can achieve tensile yield strength of 40 ksi, tensile ultimate strength of 50 ksi and 6% elongation. The proposed project is to demonstrate quality assessments with visual inspection, volumetric NDE and surface NDE; and create a mechanical and physical properties dataset that will allow potential defense customers to evaluate additive manufactured Alloy 5025 for engineering, business and performance criteria.