Abstracts of patents Abstracts of US patents prepared by Dr R.J. Hand, Department of Engineering Materials, University of Shefield, UK

US PATENTS

Segmented mandrel for forming composite articles Charlson, S.M., Kotula, S.J. and McCloy, M.R. (Hercules Incorporated, Wilmington, DE, USA) US Pat 5022845 (II June 1991) A segmented mandrel which can be used for shaping fibre composite bodies is described. The mandrel has a central axis about which it rotates and two segments which mate together along a seam to form a portion of the external surface about the shaft. A stiffener section and sealant fasten and seal the two sections together to produce a vacuum seal between them. The mandrel is disassembled after shaping.

Rapid solidification of metal-matrix composites having Ag, Au or Cu matrix Yamada, S., Tsuji, K., Takegawa, Y., Tanimura, A., Menju, A. and Yano, N. (Matsushita Electric Works, Ltd, Osaka and Unitika, Ltd, Hyogo, both of Japan) US Pat 5022932 (II June 1991) A melt of Au, Ag or Cu matrix metal has dispersed in it 0.5-20 weight% of a second metal which is insoluble with the matrix metal at ambient temperature. The whole is rapidly cooled and solidified by atomization, resulting in the formation of uniformly distributed O.l- 1 .O pm particles of the second metal in the matrix metal.

Method for casting one or several concrete products placed side by side Rantanen, H. (Oy Partek Ab, Toijala, Finland) US Par 5023030 (II June 1991) Concrete mix is fed by at least two parallel feed members placed side by side across at least one cross-section of the product to be cast. The mix is compacted to form the product, the compaction being monitored by measuring the pressure the concrete exerts on the slide casting machine at a minimum of two points so that it may be controlled to produce uniform compaction.

Method for making a fibre reinforced composite article Jones, J.D., Murphy, G.C., Mesing, T.C. and Fuhrmann, B.J. (General Electric Company, Cincinnati, OH, USA) US Pat 5023041 (11 June 1991) Plies of fibres embedded in a heat flowable matrix material are laid up in a mould to produce a preform. The mould is closed and heated until the matrix material melts and flows about the fibres and within the cavity. Excess matrix material flowing out of the cavity has a gas back pressure applied to it to force it back into the cavity and thereby pressurize the article. The pressure is main- tained whilst the matrix is solidified.

Composites Manufacturing No. 1 1993

Self-supporting ceramic structures and methods of making the same Newkirk, MS. and Weinstein, J.G. (Lanxide Technology Company, LP, Newark, DE, USA) US Pat 5024 794 (18 June 1991) A first self-supporting ceramic body, contain- ing the oxidation reaction product of a first metal and interconnected porosity, is infiltrated with a second molten metal in the presence of a liquid or solid oxidant at a temperature below the melting point of any oxidation reaction products. Thereby, that at least a portion of the porosity is filled with oxidation reaction product of the second metal.

Method of making shaped ceramic composites Kennedy, C.R. and Newkirk, M.S. (Lanxide Technology Company, LP, Newark, DE, USA) US Pat 5024 795 (18 June 1991) A permeable mass of filler is separated from a source of molten parent metal by a stratum of unstabilizable material that is permable to a vapour-phase oxidant and the oxidation reaction product of the oxidant and the parent metal. The whole is infiltrated with molten metal which reacts with the oxidant to form a self-supporting body with a ceramic stratum overlaying a ceramic composite.

Automated cutting and kitting system of composite material and method Frank, E. (The Boeing Company, Seattle, WA, USA) US Pat 5024862 (18 June 1991) A supply means for at least two types of pre-impregnated composite material is indexed such that a particular composite may be selected for cutting into a series of plies. Each ply is then shaped by cutting before being kitted and stored, with the top ply of the lay-up stored first, for subsequent use.

Alumina-zirconia-silicon carbide-magnesia ceramic cutting tools Mehrotra, P.K. and Billman, E.R. (Kenna- metal Inc, Latrobe, PA, USA) US Par 5024976 (18 June 1991)

A metal cutting insert made from a composite material comprises a homogeneous dispersion of 1.5-32.5 volume% silicon carbide whiskers; 5-17.5 volume% zirconia, of which at least 2 volume% is in the tetragonal phase; and the residue of a 0.03-3 volume% magnesia addition in an alumina matrix.

Compositions and methods for making ceramic matrix composites Allaire, R.A., Friske, M.S., Hagg, S.L. and Janas, V.F. (Corning Incorporated, Corning, NY, USA) US Pat 5024978 (I8 June 1991) The method comprises mixing inorganic reinforcing fibres with a heated thermoplastic dispersion of a powder of a ceramic matrix material, which is solid at room temperature.

Meshwork reinforced and pre-stressed concrete member, method and apparatus for making same Sekijima, K. and Kitagawa, S. (Shimizu Construction Co, Ltd, Tokyo and Dainihon

Glass Industry Co, Ltd, Sagamihara, both of Japan) US Pat 5025604 (25 June 1991) A reinforced concrete member has one set of pre-stressed elongated reinforcing members intersecting a second set of elongated reinforcing members. Each of the reinforcing members includes stacked rows of resin-impregnated and fuse-bonded textiles which fuse-bond the two sets of reinforcing members to each other. The first set of reinforcing members is pre-stressed via a set of anchoring blocks.

Method for making variable cross section pultruded thermoplastic composite ar,ticles O’Connor, J.E. (Phillips Petroleum Company, Bartlesville, OK, USA) US Pat 5026447 (25 June 1991) A length of thermoplastic product is formed so that it has a first cross-sectional shape. A portion of this is then converted to a second cross-sectional shape, so that product has a leading section with the second shape and a trailing section with the first.

Method of manufacturing moulded products of thermoplastic and inorganic materials (Chang, SC. of Shizuoka-shi, Japan) US Par 5026512 (25 June 1991) A method of moulding a material containing either a primary and secondary polymer or a primary polymer and an inorganic material and less than 1 weight% water, is described. The primary polymer is one or a blend of polyethylene, polypropylene, polystyrene, acrylonitrile-butadiene-styrene, polybutylene terephthalate, its isomer and its similar polymer, polyamide 6, polyamide 66, poly- amide 7, polyamide 11 and polyamide 12; the secondary polymer is selected from the same group and may also be cotton, hemp or rayon. The material is fed into a screw conveyor cylinder from a hopper. The temperature of the first section of the cylinder is kept below the melting temperature of the polymer whilst the rest of the cylinder is kept above the melting temperature of the polymer. The material exits the cylinder through a nozzle or die which is at a temperature within the range + 35°C and -25°C of the polymer melting temperature.

Incremental forming of thermoplastic composites (Hauwiller, P.B. and Strong, A.B. of Mt Prospect, IL and Sandy, UT, both of USA) US Pa? 5026514 (25 June 1991) A laminate of fibre-reinforced thermoplastic is prepared and at least one section is brought to a flowable condition, brought to a forming area and formed, cooled and removed from the forming area. At least one other section is then brought to a flowable condition, is brought to the forming area and formed into a different configuration from the first section, cooled and removed. This process is repeated until the product is fully formed.

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