rapid qualification and certification.

 

DESCRIPTION: NAVAIR is in need of airworthy parts for readiness and sustainment of air systems. Rapid qualification and certification of new production methods like additive manufacturing (AM) as well as legacy production methods such as forgings can dramatically improve the availability of aircraft by rapidly providing parts. Acceleration of the qualification and certification process can be done through an enterprise DT and materials data framework to support an ICME approach. This will use models and material measurements to ensure a produced part that will meet performance and airworthiness requirements [Ref 1]. Having a record of actual part microstructure will allow NAVAIR to make accurate decisions and risk assessments for multiple parts and applications, including:

�   Inspection and dispositions of forgings and castings for improper coarse grains prior to expensive machining operations.

�  Inspection of AM produced parts for directional grain structure with respect to print orientation.

�   Provide a permanent record of grain texture that may affect results of subsequent fleet inspections (e.g., eddy current inspections).

�  Provide data for real parts to compare to test coupons and ICME results for rapid qualification.

 

Characterization of metallic grain structure and orientation is a critical piece of information for model-based performance assessment. Traditional methods such as electron backscatter diffraction (EBSD) require destructive testing to characterize the microstructural and crystallographic orientations of a material. However, new laser-based, large scale orientation techniques such as spatially resolved acoustic spectroscopy (SRAS) can rapidly and nondestructively provide microstructural imaging of a wide variety of materials [Refs 2, 3]. SRAS does not require a vacuum or a polished surface. It has even been applied to AM parts [Ref 4].

 

SRAS is currently limited to flat samples. AM, forged, and cast aircraft parts of interest often have complex geometries. To meet the goal of collecting the grain structure data on the actual parts, a technology must be developed to allow grain structure measurement on complex surfaces. The system must be capable of performing microstructural crystal orientation measurements at a resolution of up to 50 microns. The technology should work on most metals, including titanium alloys, stainless steels, high-strength steels, aluminum alloys and high-temperature nickel alloys. The system should be capable of performing rapid assessments of large areas (exceeding 72 in2) and must be capable of addressing curved surfaces down to at least 0.5 in radius. The measurement technology should be able to assess on as-printed, as-cast, and as-forged surfaces without requiring machining, polishing, or etching. The technology should be capable of exporting data linked to actual part location. The technology should be able to be implemented in a production environment. The end goal is a method to rapidly and nondestructively inspect most or all surfaces of a casting, forging, or AM part so that the grain structure data can be used to assess part performance and airworthiness.

 

PHASE I: Demonstrate a proof of concept for accurate measurement of microstructure and crystallographic orientation on a curved surface. Provide theoretical evaluation of practical limitations and sensitivities for at least two materials of interest to NAVAIR for either forging or AM. Demonstrate measurement of a curved surface (radius of 2 inches or less) on at least one material. Perform validation of coupon measurements through traditional method such as EBSD by showing equivalent measurements of multiple grains and crystallographic orientations. Develop a preliminary design for a system to perform large area measurements of grain structure on parts. The Phase I effort will include prototype plans to be developed under Phase II.

 

PHASE II: Develop and manufacture a prototype system for assessment of grain structure on parts. Ensure that the system can scan grain structure on parts with complex geometries on all surfaces where line-of-sight access is possible. Demonstrate performance on components representative of actual aircraft part geometries produced by AM and/or forging. Perform validation of measurements through destructive testing and EBSD. Integrate system into a package that can be used to inspect parts and deliver prototype system to NAVAIR.

 

PHASE III DUAL USE APPLICATIONS: Refine and mature technology for production setting. Develop, test, verify and validate procedure to inspect one or more production parts in collaboration with Program Management Activities (PMAs). Identify limitations of inspection and probability of detection for critical grain structures.

Identify pass/fail criteria for inspection of parts. Prepare technology for military and commercial transition.