Processing of Metal Matrix Composites with Controlled Microstructures
Small Business Information
7960 South Kolb Road, Tucson, AZ, 85706
AbstractConventional 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).
* information listed above is at the time of submission.