TECHNOLOGY AREAS: Air Platform, Materials/Processes

ACQUISITION PROGRAM: Joint Strike Fighter Program

OBJECTIVE: Develop enabling technology that delivers a practical weld repair solution that will meet or exceed fatigue requirements of Inconel airfoils in an integrally bladed rotor (IBR)/blisk.

DESCRIPTION: State-of-the-art military turbine engines incorporate IBRs, which are one piece components consisting of blades and a disk (blisks), in the compression system. Their purpose is to reduce weight through part count reduction and improve performance and maintainability. However, to maintain affordability, the need for weld repairs of either partial or full blades is warranted to avoid expensive IBR/blisk replacements resulting from foreign object damage (FOD) to the airfoils. No adequate technology exists today to repair fielded engines. For alloys commonly used in fans and compressors, current pre- and/or post-weld heat treatment practices, as part of the repair of airfoils, result in unacceptable micro-structural degradation in the highly stressed disk portion of the IBRs/blisks. Exposing the undamaged airfoils to needless heat treatment at every repair leads to significant reduction in their structural capability. A novel and enabling weld repair technology that will permit independent repair and optimization of airfoil and disk material properties is needed to retain and restore the high cycle fatigue (HCF) characteristics of IBRs/blisks. The technology should be able to meet these requirements in addition to addressing affordability and maintainability requirements of advanced military propulsion power plants.

PHASE I: Conceptualize, evaluate, and determine the feasibility of repair techniques that will restore the airfoils in an IBR/blisk to their original material properties after a FOD event. Demonstrate cost-effectiveness of the proposed technique. Identify hardware and tools needed for the procedure. Evaluate improvements over current repair methodologies.

PHASE II: Demonstrate the technique and subsequent improvement in structural integrity and HCF performance in a rig and engine environment. Address potential adverse affordability issues and identify mitigating solutions.

PHASE III: Integrate the technology into a manufacturing environment at an original equipment manufacturer (OEM) or depot.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: The ability to repair fielded turbine engines at low cost is desirable for the commercial sector. Expensive and redundant repairs could be minimized by employing this technology to reduce time off wing of turbine engines.

REFERENCES:
1. Ellison, Keith A., Joseph Liburdi and Jan T. Stover. "Low Cycle Fatigue Properties of LPMTM Wide-Gap Repairs in Inconel 738." Liburdi Engineering Limited, Hamilton, ON, Canada. http:/doc.tms.org.

KEYWORDS: Inconel; IBR; Integrally Bladed Rotor; Blisk; Foreign Object Damage; Repair Techniques

TPOC: (301)757-0472
2nd TPOC: (301)757-0407

** TOPIC AUTHOR (TPOC) **

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