D. Meath, L. Brown
Advanced Technology International,
United States
Keywords: nanoparticles, aluminum, aluminum repair, MRO, metallography
Summary:
At present, there are many Navy aircraft parts that have minor damage and cannot be repaired due to lack of an approved method of repair. These may be large parts with long production lead times or lack of a source at all. An approved weld repair process would allow these parts to be restored and used to maintain readiness of aircraft that may be otherwise grounded due to lack of replacement parts. Aluminum Alloy 2024 and 7075 are commonly used for aviation structural components across multiple platforms, yet these alloys are found to be difficult to weld due to their hot cracking susceptibility during fusion welding. These alloys are used for highly stressed structural applications while providing an excellent strength to weight ratio. To improve sustainability of legacy aircraft, it is required to develop weld repair technologies as an asset to Maintenance, Repair, and Overhaul (MRO) activity. Given the current state of conventional welding, Gas Tungsten Arc Welding (GTAW) is the preferred repair process. Leveraging nanoparticle technology to enhance solidification processes such as castings, this project investigates the use of new nanoparticle-enhanced weld consumables introduced to market for fusion welding of high strength aluminum alloys 2024 and 7075 with application to MRO operations. Round robin weld trials were performed along with limited weld characterizations in metallography, mechanical performance tests, and corrosion evaluation. Results of the project have provided enabling data to pursue continued development in support of future qualification efforts for NAVAIR MRO operations. This project was strictly a 6.2 type project for the Navy’s ManTech Center for Naval Metalworking (CNM) that has since concluded. As such, the project was strictly research based and without requirement of implementation. Throughout the duration of the project, the team worked to build a set of welding tenets for utility of nanoparticle enhanced weld wire that assist in the rapid repair of fatigued and failed aluminum components and assemblies.