Additive Repair of 7000 Series Aircraft Structures via High-Pressure Cold Spray Processing (HP-CSP)

Aircraft components experience in-service degradation by several mechanisms. These include mechanical damage, wear and abrasion damage, and corrosion damage. Each of these damage methods can cause material loss and localized damage formation such as pitting, which can then results in stress concentrations. Once the section thickness reduction is significant enough or the stress concentration is too large, static or cyclic loading can result in part failure. The structural integrity of damaged aircraft components has traditionally been restored through simple blending if the part is sufficiently thick, or through welding which can introduce cracking, tensile stresses, and heat affected zones.

Traditional aircraft repair methods can be invasive, time-consuming, disruptive and reduce mission readiness, demonstrating a need for reliable, efficient, and effective solutions. High-Pressure Cold Spray Processing (HPCSP) is a novel, solid-state additive manufacturing method which can deposit high quality materials with mechanical properties that rival the performance of their wrought counterparts.

In this ongoing effort, presented will be the most recent results on the fatigue strength of aluminum 7000 series aircraft skin and through-hole structures for fasteners, via HPCSP. These repair solutions can be at point of need, which significantly increasing mission readiness and reduces overall cost and manual labor hours. Currently this repair technology is being developed using helium as the processing gas, however since helium is in short supply, VRC is making efforts toward developing similar aluminum repair and retrofit deposits with hydrogen processing gas instead. Fatigue test conditions will be presented at both fully reversable R=-1 and tension-tension R=0.1.