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 from cyclical loading induced fatigue along with material loss from abrasion and wear. Corrosion induced by moisture and salt-laden air is another material loss mechanism, often in the form of “pits” that both reduce load bearing area and create stress concentrations on top. The structural integrity of damaged aircraft components has traditionally been restored via conventional welding which often introduces additional issues, such as cracking in weld areas with high tensile residual stresses and weld defects, and mechanical failures in heat-affected zones that are weakened from the welding process.

Traditional aircraft repair methods can be invasive, time-consuming, disruptive and reduce mission readiness, demonstrating a need for reliable, efficient, and time effective innovative repair methods. Cold Spray Processing (CSP) is a novel, solid-state additive manufacturing method of developing metallic based coatings with fine microstructures, high tensile strength and hardness, superior wear resistance, tailorable anodic/cathodic corrosion protection, and improved fatigue life compared to the base substrate.

In this work, a repair example will show how 7XXX series aircraft skin and parts can be repaired in-situ with high-pressure CSP instead of being removed for repair or replacement, significantly reducing project complexity, downtime, and cost. Electron microscopy results demonstrate the quality of the deposits the microstructure. The added benefits from the beneficial fine microstructure, lack of solidification induced defects, and compressive stress state of the coating will be presented in the context of the significantly improved fatigue life, by 100%, fully reversed (R= -1) and tension-tension (R= +0.1) fatigue testing.