Showing papers on "Metal matrix composite published in 1984"

Arc spray fabrication of metal matrix composite monotape

Abstract: Arc metal spraying is used to spray liquid metal onto an array of high strength fibers (10) that have been previously wound onto a large drum (12) contained inside a controlled atmosphere chamber (18) This chamber is first evacuated to remove gaseous contaminants and then backfilled with a neutral gas up to atmospheric pressure This process is used to produce a large size metal matrix composite monotape

Method of preparing metal matrix composite materials using metallo-organic solutions for fiber pre-treatment

Abstract: Glass or ceramic fibers or other fibers such as graphite properly protected by a suitable adherent ceramic or metal coating are immersed in a liquid metallo-organic solution containing a noble metal compound as a primary ingredient, then dried and fired in air or in a slightly oxidizing atmosphere so as to produce a noble metal coating on the fibers. Fibers may be in the form of individual filaments, as a multifilament tow or yarn or as a woven fabric. The fibers coated with a nobel metal are then incorporated into a metal matrix composite material by immersion in a molten bath of the desired matrix metal, placing the fibers in a suitable mold and casting the molten matrix metal around them or placing the fibers between solid sheets of matrix metal and effecting consolidation by diffusion bonding. The coating thickness on the fibers should be at least 0.30 microns and should not exceed 0.50 microns. By staying within this range, adequate wetting by the metal matrix material coupled with maximum matrix purity are achieved. Optimum reproducibility of fiber infiltration and optimum effectiveness of fiber strengthening in the composite are achieved at the upper end of this range.

Simple and precise measurements of fibre volume and void fractions in metal matrix composite materials

Abstract: A method for determining the fibre volume fraction, V f and the void fraction, V g, in a metal matrix composite (MMC) material is described. These quantities are determined from specimen weight measurements in air and in a liquid using a laboratory balance. For a material without voids, V f can be determined with an uncertainty less than 0.5% with a balance precision of 0.01%. By making the same measurements before and after etching away the matrix, using the same balance precision, V f and V g can be determined to an uncertainty of about 3 and 6%, respectively. It is also shown theoretically that by indenting a specimen containing no fibres and only a uniform distribution of small voids, the void fraction can also be determined from weight measurements before and after indentation.

Metal matrix composite made with reduced interface reactions

Abstract: A metal matrix composite is produced by closely aligning together a sheet of hydrided or hydrogenated alloy with a filament preform at a relatively low temperature. The resulting metal matrix will have a minimum of excessive chemical reactions at the alloy-filament interface thereby allowing the composite to achieve theoretical mechanical property values.

Loss Factors Measured in Metal Matrix Composite Materials.

Abstract: : The resonant dwell technique was used to measure loss factors at the fundamental frequency of a number of cantilever beam samples (100 to 200 Hz). Nine different metal matrix composites, three unreinforced base metals, and eight configurations of FP(AL203)/ZE41AMg were tested at three temperatures and four peak sample stress levels below 30,000 psi. The results indicate increasing loss factor with increasing stress level. Loss factors of all composites except graphite/aluminum composites were lower than those of the corresponding base metal. For FP/ZE41Mg composites, higher losses were observed with heat treatment, lower fiber volume fraction, and + or - 221/2 deg fiber orientation. Trends of loss factor with temperature varied with material type. (Author)

Ultrasonic Measurements of Elastic Moduli of Thermally Cycled Metal Matrix Composite Precursor Wires

Abstract: Metal matrix composite structures are often made by the consolidation of precursor wires typically on the order of 1 mm in diameter. The elastic and mechanical properties of the consolidated parts depend critically on the elastic and mechanical properties of the precursor wires. The consolidation process involves hot pressing at elevated temperatures. The final end-item products may also be subjected to elevated temperatures in their normal use cycles.