Showing papers on "Metal matrix composite published in 1981"

Carbon-reinforced metal-matrix composites

Abstract: A carbon fiber reinforced metal matrix composite is produced by metal oxide coating the surface of the fibers by passing the fibers through an organometallic solution followed by pyrolysis or hydrolysis of the organometallic compounds. The metal oxide coated fibers so produced are readily wettable without degradation when immersed in a molten bath of the metal matrix material.

Metal matrix composite structural panel construction

Abstract: Lightweight capped honeycomb stiffeners 18 for use in fabricating metal or metal/matrix exterior structural panels 14 on aerospace type vehicles 10 and the process for fabricating same are disclosed. The stiffener stringers are formed in sheets (FIG. 6), cut to the desired width and length and brazed in spaced relationship to a skin 16 (FIG. 2) with the honeycomb material serving directly as the required lightweight stiffeners and not requiring separate metal encasement for the exposed honeycomb cells.

Method of forming fiber and metal matrix composite

Abstract: Improved method of fabricating boron fiber and aluminum matrix composite structures, especially gas turbine compressor blades having titanium metal skins. Titanium skins (32, 32') and boron aluminum composite cores (34) are preformed by gas pressure and hard dies prior to hot pressing. The composite sheets (34) of the core are preformed with the use of expendable carrier sheets (36, 38) which hold the stacked sheets firmly as both the carrier sheets and composites are shaped through moderate temperature and gas pressure against a hard die (46). The preforming permanently shapes and lightly bonds the composite sheets. The skins (32, 32') are preformed in an analogous process using gas pressurization of a metal envelope into die cavities (24, 24'). The skins and composite core are then hot pressed in hard dies (54, 54') to form the finished part.

A Study of Solid Metal/Ceramic Reactions

Abstract: In advanced energy systems, ceramics may allow higher operating temperatures for greater efficiency. However, compressive contacts at joints with metals are required by the poor tensile behavior of ceramics. Compression at these interfaces excludes oxygen, and oxides do not form. Reactions under inert or reducing conditions (as in metal matrix composites) have been studied,(1,2) as have reactions of complex superalloys with SiC,(3) Si/SiC(4) and Si3N4.(5) The reactions were complex, dictating a phenomenological study with no treatment of their basic nature or the phase equilibria. With a model alloy containing only Ni, Cr and A1, the present experiments and analyses are an attempt to gain a more basic understanding of metal/ceramic reactions.

Fatigue Behavior of Silicon-Carbide Reinforced Titanium Composites

Abstract: The low cycle axial fatigue properties of 25 and 44-fiber volume percent SiC/Ti(6Al-4V) composites were measured at room temperature and at 650°C. At room temperature, the S-N curves for the composites showed no anticipated improvement over bulk matrix behavior. Although axial and transverse tensile strength results suggest a degradation in silicon-carbide fiber strength during composite fabrication, it appears that the poor fatigue life of the composites was caused by a reduced fatigue resistance of the reinforced Ti(6Al-4V) matrix. Microstructural studies indicate that the reduced matrix behavior was due, in part, to the presence of flawed and fractured fibers created near the specimen surfaces by preparation techniques. Another possible contributing factor is the large residual tensile stresses that can exist in fiber-reinforced matrices. These effects as well as the effects of fatigue testing at high temperature are discussed.