Rapid Repair of Corroded Fastener Holes

Global Engineering and Materials, Inc. (GEM), along with its team member Virginia Tech (VT), proposes a new approach for quick repair of corroded fastener holes using an emerging solid-state process, additive friction stir deposition (AFSD). AFSD integrates the friction stir principle with a robust material feeding mechanism to enable site-specific deposition. Renowned for low cost, high speed, ease of use, and high repair quality, AFSD will be used to repair the oversized hole after removal of the corroded region, wherein a seamless bond will be created between the side wall and the repaired material with strong adhesion and great promise for restoring the fatigue and static strength. Our Phase I feasibility study will consist of systematic efforts comparing plates with the original fastener hole versus plates repaired by our new AFSD approach. The post-repair mechanical properties at specific points will be investigated using nano-indentation, while both static and fatigue tests will be conducted to validate AFSD’s capability of restoring the component’s remaining fatigue life with acceptable static strength. To optimize the deposition process for repair, numerical simulations will be performed to explore the effects of residual stress, initial distortion, and bonding strength on the mechanical performance of repaired fastener holes.