Additive Repair of Aircraft Components 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. Cold Spray Processing (CSP) 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.

This work discusses how high-pressure cold spray improves the fatigue life of 357 cast aluminum aircraft parts, and can restore the fatigue strength of aluminum 7000 series aircraft skin and through-hole structures for fasteners. These repair solutions are at point of need, significantly increasing mission readiness and reducing overall cost and labor hours. While this repair technology has been developed using helium as the processing gas, efforts have been made to qualify these repairs with both nitrogen and air, as well. Fatigue test conditions will be presented at both fully reversable R=-1 and tension-tension R=0.1.