Project Title:

Innovative Processing for Metal Matrix Composites With Controlled

Materials and Electrochemical Research (MER) Corporation
7960 S. Kolb Road
Tucson, AZ 85706

93-1-04     18   1980

Innovative Processing for Metal Matrix Composites With Controlled
Microstructures

Abstract:

Conventional composite processing techniques are presently unable
to  fabricate unidirectional fiber reinforced composites based on
small diameter fibers, for example, ~5-20 um in diameter. The
primary problem is one of infiltration of the matrix in between
the fibers and maintaining a reasonably constant fiber spacing.
An innovative MMC processing technique is proposed wherein,
starting with a ceramic fiber tow, each fiber would be spread and
individually coated with the matrix material by a plasma-assisted
sputtering process. The continuous coated fiber can then be
utilized in a variety of ways, such as fiber lay-up for uniaxial
panels or weaving in 2 or 3 dimensional architecture, followed by
hot consolidation to obtain advanced composites with desired
fiber orientation. Such a composite processing technique is also
amenable to tailoring of the fiber-matrix interface by the
addition of a very thin coat of metals such as Cr or Ti (which
improve adhesion of the matrix to the fiber) prior to deposition
of the matrix in a single step. Further, the fiber volume
fraction within the matrix can be varied by varying the thickness
of the coating. By coating all the fibers to a given thickness,
an uniform fiber spacing can be obtained in a hot-consolidated
state. This composite processing technique is also flexible
enough to accommodate a starting compliant/compensating layer, if
necessary, to improve the thermal cycling performance of these
composites (especially those based on relatively brittle
matrices).

MMCs are expected to present a significant market in the near
future for commercial and military aerospace engines and other
hot-structural applications. This route to the synthesis of these
composites with a tailored interface is expected to by more
attractive from microstructural uniformity and associated
mechanical property considerations.

Plasma Sputtering, FeCrAlZr-Al203, Superalloys, Metal Matrix
Composite