PROJECTED CMMC LEVEL REQUIREMENT
Level 2 (Self)
TECHNOLOGY AREAS
None
MODERNIZATION PRIORITIES
Advanced Materials
|
Sustainment & Logistics
KEYWORDS
Landing Gear; Coatings; Metal-matrix; Ceramics; High-Strength Steels; Hard Chrome
OBJECTIVE
Develop an integrated metal matrix for high strength steels.
DESCRIPTION
Landing gear components are limited to the use of high strength steels due to their harsh loading applications and various environmental conditions. Typically, high strength steels are used to survive the load requirements. The two technologies currently applied to most landing gear components are Hard Chrome and high velocity oxygen fuel (HVOF). Each has their disadvantages that affects landing gear components. A replacement for Hard Chrome and HVOF is required to improve the readiness and safety of landing gear components.
Hard Chrome's main disadvantage is that it hides corrosion underneath the chrome plating which can lead to stress corrosion cracking in high strength steels. This failure mode would cause the complete loss of a landing gear system as the landing gear essentially snaps into pieces due to high stresses of landing. If corrosion is found before stress corrosion cracking occurs it still leads to the complete scrapping of landing gear components. This is due to Hard Chrome having no repair method. The only option for Hard Chrome is to replace, remove, and then reapply which takes days of machining and post machining. In addition to the machining, the application requires hazardous chemicals and produces waste that creates a health and safety risk to the fleet and its manufacturing personnel. Lastly, another risk with Hard Chrome is the dimensional limitations it provides. If too little or too much Hard Chrome is applied, the coating will immediately delaminate and damage landing gear and hydraulic components due to the foreign object debris (FOD) inside the system.
HVOF comes with its disadvantages as well. HVOF requires extremely low surface roughness on the pistons which have poor tribology. The poor tribology causes the hydraulics seals to perform dry and wear the seals away extremely quickly. Hydraulic fluid cannot stick to the walls of the piston due to the low surface roughness.
On top of the hydraulic disadvantages, the surface roughness requires precision post machining for long durations to survive the landing gear environments. In the fleet, the main issue seen with HVOF is spalling when the landing gear experiences high strains. When this occurs, the landing gear components must be removed and replaced.
This topic seeks an innovative solution that provides an integrated metal matrix for high strength steels that boosts the performance of and extends a component's survivability and improves a system's operational readiness and lifecycle costs. Current technology for titanium uses waveform energy. The process generates a targeted physical reaction within a substrate, activating the substrate at an atomic level for precise placement and gradient depth control of an integrated infusion. This infusion results in a matrix composite material that leverages the strengths of both components. The chemical bonding between a ceramic and the titanium alloy involves a combination of covalent and ionic characteristics sharing and exchanging of electrons. This combination enhances the mechanical properties of the composite material, such as properties and porosity mitigation for corrosion protection, hardness for wear resistance, thermal stability, and overall durability, resulting in a metal-matrix suitable for various high-performance applications. Current technology can tailor characteristics such as hardness, electrical conductivity, thermal and oxidation, and mechanical strength. These meticulous adjustments enable the creation of the matrix with specific, desired functionalities, enhancing their performance in various applications to defeat corrosion, wear, erosion, thermal, and other challenges. For instance, a metal matrix composite gradient depth infusions of titanium nitride (TiN) achieved hardness ratings of 2800-3100HV (micro-Vickers). Currently, the process is limited to transition metals; however, there is a need to adapt and develop it for application to high strength steels. This innovative solution will provide the benefits of both Hard Chrome and HVOF while eliminating the current limitations of the respective coatings.
PHASE I
The Phase I Option focuses on identifying a potential coating by evaluating the compatibility of metal integration properties with the proposed high- strength steel. This includes determining whether a metal matrix can be successfully formed and sustained on the high strength steel surface. Attention will be given to identifying optimal surface characteristics such as roughness, texture, patterning, and placement adjustments to enhance oil retention and lubricity within landing gear components. Desired material properties and suitable tooling methods will be established to achieve the required metal integration. Sample coupons will be created as feasibility evidence for developing the coating process. This will be followed by analysis and characterization of the metal integration within high-strength steel substrates. Finally prototype plans will be developed to realize initial geometric characteristics for a titanium alloy component tailored to the project's specifications.
PHASE II
Develop prototyped landing gear components with internal components using the developed integrated metal matrix. Perform landing gear qualification testing to ensure prototyped integrated metal matrix components can withstand landing gear environments.
Establish wear patterns, production process, and related properties.
PHASE III DUAL USE APPLICATIONS
Integrate the landing gear components into fleet aircraft.
Metal matrix composites are employed in advanced industries due to their high modulus and strength, favorable wear and corrosion resistance, and other good properties at elevated temperatures.
Aerospace: High-temperature components like exhaust nozzles, heat shields, and other components.
Engine components: Turbine disks, impellers, and other engine parts requiring high strength-to-weight ratios.
Structural components: Structures where lightweight and high strength are crucial.
Automotive: Engine parts like Piston rings, brake discs, and rotors benefit due to their high strength, wear resistance, and thermal conductivity.
Lightweight construction components to reduce vehicle weight, improving fuel efficiency.
Electronics: Thermal management heat sinks and electronic packaging to dissipate heat and improve device performance.
Industrial: Cutting tools due to their high strength and wear resistance. Wear-resistant parts in industrial machinery and tools where high wear resistance is needed.
REFERENCES
Chen, L-Y.; Qin, P.; Zhang, L. and Zhang, L-C. "An overview of additively manufactured metal matrix composites: preparation, performance, and challenge." International Journal of Extreme Manufacturing, June 20, 2024. https://iopscience.iop.org/article/10.1088/2631-7990/ad54a4
Chandrasekar, P.; Balusamy, V.; Chandran, K.S. Ravi and Kumar, Harish. "Laser surface hardening of titanium-titanium boride (Ti-TiB) metal matrix composite." Scripta Materialia, Volume 56, Issue 7, April 2007, pp. 641-644, ISSN 1359-6462. https://doi.org/10.1016/j.scriptamat.2006.11.035 (https://www.sciencedirect.com/science/article/pii/S135964620600844X)
