Thermal Processing for Enhanced Additive Repair of Aluminum Structures by Cold Spray Deposition
Abstract
We propose the development of enhanced cold spray deposition approaches foradditive repair of aluminum alloy structures on naval aircraft. The high strengthaluminum alloys (2xxx and 7xxx series) are used extensively in the construction ofaircraft structural components, but these alloys are susceptible to pitting, intergranular corrosion and stress corrosion cracking. Additionally, these alloys are challenging to repair because they are not weldable by traditional fusion welding. As such, additive repair by cold spray deposition (ARCS) is being developed to repair and to return components to fleet service. Cold spray is a material deposition process that uses powder particles sprayed at high velocities (300-1200 m/s) onto a substrate. The powder particles plastically deform upon impact, creating a metallurgical bond between the powder andthe substrate. While progress is being made on ARCS for functional and structural repairs, the as-sprayed materials still require improvement for deposition efficiency, ultimate tensile strength, ductility, and low-cycle fatigue life. These properties could all be improved by optimized powders and by the use of in situ laser heat treatment during cold spray deposition. We will examine two types of thermal processing to enhance the mechanical properties of additive repairs produced by cold spray deposition. First, we will use a novel heat treatment method on the feed-stock powder which will normalize the microstructure of the powder particles. Second we will implement, for the first time, laser-assisted cold spray (LACS) for in situ heating of the material during deposition. Both of these approaches will improve the deposition efficiency, the ultimate tensile strength, the ductility, and fatigue performance of the deposited material. These enhanced ARCS methods will be applied both to structural, e.g. fastener hole, and functional, e.g. door sill, repairs.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 26, 2018
- Source ID
- N000141812519
Entities
People
- Luke N. Brewer
Organizations
- Office of Naval Research
- United States Navy
- University of Alabama