Additive Repair via Cold Spray Deposition in Aluminum Load-Bearing Structures
Abstract
Summary Statement of Work We propose the development of cold spray deposition for additive repair of load-bearing, aluminum alloy structures on naval aircraft. The high strength aluminum alloys (2xxx and 7xxx series) are used extensively in the construction of aircraft structural components (e.g. wing or fuselage components). These alloys are susceptible to pitting, intergranular corrosion and stress corrosion cracking due to the intermetallic precipitates which give them their strength. Additionally, 2xxx and 7xxx series alloys are challenging to repair because they are not weldable by traditional fusion welding; however, cold spray deposition could be used to repair these surface defects/damage to return components to fleet service. Cold spray is a material deposition process that uses powder particles sprayed at high velocity (300-1200 m/s) onto a substrate. The powder particles plastically deform upon impact, creating a metallurgical bond between the powder and the substrate. Cold spray deposition has been successfully used to add material to repair erosion and corrosion damage in non-load bearing magnesium and aluminum structures in aircraft. The repair of load bearing structures is more challenging as applied static and dynamic loads demand more from the repaired material both in an adhesive and cohesive sense. We will examine two types of additive repairs: a replaced ring and an additively constructed fuselagelug- bracket. These two repairs represent an increased emphasis on the cohesive properties of the repair compared to adhesion between the repair and the structural substrate. In each case, we will investigate the connections between the cold spray processing parameters, the resultant microstructures, the mechanical properties of the repaired material, and the mechanical performance of the repaired component. We also compare the differences between AA7075 and AA2024 materials for additive repair. For both types of repairs, we will pay special attention to the details of the adhesion between the substrate and the repair. Quantitative low cycle and high cycle fatigue measurements will be used to assess the reliability of these types of additive repair. We will also perform diffraction-based residual stress measurements to quantify the residual stresses generated and their impact of fatigue behavior.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512133
Entities
People
- Luke N. Brewer
Organizations
- Office of Naval Research
- United States Navy
- University of Alabama