N231-072 TITLE: High Temperature Ceramic Yarn from Discontinuous Silicon Carbide (SiC) Fibers

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Hypersonics; Space

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.

OBJECTIVE: Develop a process in which short silicon carbide (SiC) fibers are fabricated into a yarn capable of integration into traditional weaving or braiding systems used to produce high strength, high temperature ceramic matrix composites (CMCs).

DESCRIPTION: Advanced aerospace vehicles and munitions, including hypersonics, rely on CMCs in order to operate under harsh aerothermal environments. Carbon-carbon (C/C) composites are most frequently employed, but CMCs incorporating higher temperatures materials, such as Silicon Carbide (SiC), Hafnium Diboride (HfB2), Zirconium Diboride (ZrB), Hafnium Carbide (HfC), are being investigated and are important for improved performance. One of the greatest challenges associated with the production of high performance CMCs is the sourcing of needed materials, notably fibers. The majority of carbon fiber manufacturers are foreign companies, and even procuring carbon fiber, which has been a mature technology for more than 50 years, has its challenges. Additionally, much of the world production of higher temperature SiC fibers is controlled by foreign companies.

While most fiber processes utilize continuous fiber filaments, short fibers offer the potential for alternative manufacturing methods and material. Short fibers in yarn form can increase the drapeability of textiles, improve the processability of CMCs, and allow tuning of the thermal conductivity of the resulting composite. It is anticipated that developing this technology will result in an expanded domestic fiber supply for high temperature CMC components. To reduce supply chain risk and open up additional sources of fiber for the Navy�s future needs, this SBIR topic aims to develop a manufacturing process to produce high temperature yarn from short SiC fibers.

The yarn will initially be constructed from SiC fibers, but it is desired that the process is material independent in order to accommodate other high temperature materials. In order to have broad application, the yarn must be of sufficient strength to interface with current weaving and braiding processes used in the construction of CMC preforms and textiles. For the yarn to yield high quality CMC components, the fibers must have good mechanical and thermal properties and be sufficiently aligned (target values to be provided upon contract award). Additionally, fibers must be of sufficient length in order to approach the properties of CMC yarns constructed from carbon fibers (properties include tensile strength, thermal shock, creep resistance, high temperature resistance). Required ranges to be provided upon contract award.

The Phase II effort will likely require secure access, and SSP will process the DD254 to support the contractor for personnel and facility certification for secure access. The Phase I effort will not require access to classified information. If need be, data of the same level of complexity as secured data will be provided to support Phase I work.

It is probable that the work under this effort will be classified under Phase II. The prospective contractor(s) must be U.S. Owned and Operated with no Foreign Influence as defined by DOD 5220.22-M, National Industrial Security Program Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Security Service (DSS). The selected contractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances, in order to perform on advanced phases of this contract as set forth by DSS and SSP in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material IAW DoD 5220.22-M during the advance phases of this contract.

PHASE I: In Phase I, companies are expected to complete the following:

� Design and demonstrate feasibility of a manufacturing process which is capable of producing yarn from discontinuous SiC fibers.

� Identify a source for superior SiC fibers, ensure their high strength and temperature properties, and develop plans to obtain a sufficient supply of these fibers for Phase II and Phase III of this project.

� Produce sample yarn from short ceramic fiber, and characterize it in order to ensure that it could meet the needs given in the description.

 

Although initial solutions may be at the benchtop scale, the Phase I effort will include plans to moderately scale up the solution under Phase II.

The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype system in Phase II.

PHASE II: In Phase II, companies are expected to complete the following:

� Produce a prototype system for manufacturing SiC yarn by improving upon and developing the approach from Phase I.

� Iterate on the manufacturing process in order to improve efficiency and yarn quality.

� Understand the impact of fiber characteristics on the manufacturing process and the resulting yarn through mechanical testing, imaging, and analysis.

� Provide SiC yarn to the Navy for testing and evaluation in processes which normally rely on fiber tows.

 

It is probable that the work under this effort will be classified under Phase II (see Description section for details).

PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the technology to Navy use. Finalize development, based on Phase II results, and aid in supplying the Navy with material needed to manufacture and test CMC components under representative flight conditions. The need for additional domestic sources of fiber exist within other branches of the DoD, and potential uses for this technology exist in the commercial and aftermarket composite industry as well. Currently, short fibers are milled for filler material or used to manufacture non-woven isotropic composites. The compositing process often generates significant scrap fiber. Additionally, ceramic fiber can be extracted from recycled composites. Instead of processing these fibers in low performance and value composites, they could be converted to a yarn and used in high quality components, similar to continuous fiber.

REFERENCES:

1.       McDanels, D.L. Analysis of stress-strain, fracture, and ductility behavior of aluminum matrix composites containing discontinuous silicon carbide reinforcement. Metall Mater Trans A 16, 1105�1115 (1985).

2.       U. Papenburg, S. Walter, M. Selzer, S. Beyer, H. Laube, G. Langel, U. Papenburg, S. Walter, M. Selzer, S. Beyer, H. Laube and G. Langel. Advanced ceramic matrix composites (CMC's) for space propulsion systems. American Institue of Aeronautise and Astronautics, Inc. 33rd Joint Propulsion Conference and Exhibit, Seattle, WA, 06 July 1997 � 09 July 1997.

3.       S. Schmidt, S. Beyer, H. Knabe, H. Immich, R. Meistring, A. Gessler. Advanced ceramic matrix composite materials for current and future propulsion technology applications. Acta Astronautica, Volume 55, Issues 3�9, 2004, Pages 409-420, ISSN 0094-5765.

 

KEYWORDS: Hypersonics; silicon carbide; ceramic matrix composites; manufacturing; yarn; weaving; thermal protection system

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