NASA 1999 SBIR Phase I


PROPOSAL NUMBER 99-1 03.07-4242 (Chron: 991610 )

PROJECT TITLE

Brazing Silicon CMCs to Superalloys for Turbomachinery Applications


TECHNICAL ABSTRACT (LIMIT 200 WORDS)

Laminated ceramic matrix composites are being considered for a number of engine structural applications in NASA's Reusable launch Vehicle (RLV) system. However, technology to reliably attach CMC parts to superalloy structural components currently does not exist. Two key obstacles in ceramic to metal joining are the non wetting nature of ceramics and the large thermal expansion mismatch between these adherends, leading to high residual stresses. In addition, laminated CMCs have low interlaminar shear and tensile strengths (3 to 4 ksi) and are particularly susceptible to premature failure due to residual stresses.

In Phase I, Foster-Miller will demonstrate an innovative braze joining technology that will enable high strength joints between SiC matrix composites and a representative superalloy. The work will include finite element analyses of the joint as well as joint specimen fabrication and testing. We have teamed with a major rocket engine manufacturer who has committed to providing engineering support in the design and test planning areas.

The Phase II program will involve design and process optimization followed by scale-up to attachment of a representative rocket engine component.


POTENTIAL COMMERCIAL APPLICATIONS

The CMC to superalloy attachment technology developed under this Phase I will have many other aerospace and industrial applications. These include: IHPTET based gas turbine engines, land based turbines, reentry vehicle structures, hot gas filters, chemical processing equipment, earth moving equipment, diesel engines, etc. Performance requirements for the next generation systems in these applications mandate the use of ceramic and CMC components. However, to make this possible, a reliable CMC-metal attachment method must be developed, as proposed under this program.


NAME AND ADDRESS OF PRINCIPAL INVESTIGATOR (Name, Organization Name, Mail Address,

City/State/Zip)

Uday Kashalikar

Foster-Miller, Inc.

350 Second Ave.

Waltham , MA 02451 - 1196


NAME AND ADDRESS OF OFFEROR (Firm Name, Mail Address, City/State/Zip)

Foster-Miller, Inc.

350 Second Ave.

Waltham , MA 02451 - 1196