molten metal is placed in contact with a permeable mass comprised of a boron donor material and a carbon donor material. The temperature is maintained so that the molten metal infiltrates the permeable mass and reacts with the boron carbide to produce at least one boron-containing compound and the carbon-containing donor material to produce at least one carbon-containing compound. The reaction is continued until a self-supporting body comprising at least one parent metal boron-containing compound is produced. Microstructurally toughened metal matrix composite article and method of making same Prewo, K.M., Nardone, V.C. and Strife, J.R. (United Technologies Corporation, Hartford, CT, USA) US Pat 4 885 212 (5 December 1989) Metal rods are placed longitudinally in a metal container with a substantially continuous inner surface which extends along an axis from an open container. The voids between the rods are filled with a particulate mixture of metallic and ceramic particles and the whole is consolidated at elevated temperatures and pressures to form the composite article. Method of making composite articles Spain, R.G. (Airfoil Textron Inc, Lima, OH, USA) US Pat 4 885 973 (12 December 1989) A braided preform is made from a plurality of non-fugative braider fibres and fugative fibres. The latter fibres are selectively removed from the preform to form matrix ingress passages in the preform. The preform is then impregnated with a matrix material. Method for forming a fibre-reinforced metal sheet Utsunomiya, S., Okumura, M. and Morita, T. (Agency of Industrial Science and Technology and Mitsubishi Denki Kabushiki Kaisha, Tokyo, Japan) US Pat 4 886 108 (12 December 1989) Fibres and a matrix are combined together in a wire preform and a number of these are placed side by side in a predetermined direction. These preforms are then simultaneously heated with both CO 2 and YAG lasers and are pressed between rollers whilst they are still hot. Method of making metal matrix monotape ribbon and composite components of irregular shape Ammon, R.L. and Borough, B. (Westinghouse Electric Corp, Pittsburgh, PA, USA) US Pat 4 886 202 (12 December 1989) A cylindrical drum is wrapped with an array of fibres disposed on a spiral of predetermined pitch such that each wrap of the array is adjacent to the previous one. This is overlayed with molten metal using an arc
spray and on solidification the overlay is cut and removed from the cylinder in such a fashion that none of the fibres is cut to form a metal-matrix monotape. The irregular object is wrapped with this tape with the wraps again being adjacent. Method of manufacturing reinforced optical fibre Pinsou, G.T. (The Boeing Company, Wichita, KN, USA) US Pat 4 886 562 (12 December 1989) An elongated optical fibre is coaxially wound with reinforcing fibre to a selected density per unit length. The whole is immersed in a resin bath for a predetermined time to form a flexible resin matrix among the reinforcing fibres. The coated fibre is then passed through a sizing die to both remove excess resin and to shape it before being oven cured. An external coating is then applied and the resultant whole is passed through a second sizing die to remove excess coating and to shape the coated, reinforced fibre. Process for producing a f'flament-containing composite in a ceramic matrix Singh, R.N. and Gaddipati, A.R. (General Electric Company, Schenectady, NY, USA) US Pat 4 886 682 (12 December 1989) A matrix-forming ceramic material is mixed with an organic binder and the resulting mixture is formed into a tape. Filaments with a diameter of at least 50 ~tm and a length of at least 10 times the diameter are spaced in a substantially parallel fashion in a layer and this layer is laminated between two of the tapes and the organic binder is burnt out. The resulting structure is hot-pressed until less than 5% volume porosity is achieved. No significant reaction occurs between the filaments and the matrix and the matrix has a thermal expansion coefficient from lower than that of the filaments to about 15% higher. The filaments comprise at least I0 vol % of the composite body. Method of making explosively bonded multilaminar composite metal plate Hardwick, R. (Imperial Chemical Industries pic, London, UK) US Pat 4 887 761 (19 December 1989) A number of metal plates are assembled with stand-off space between adjacent plates. A driver plate with a mass at least equal to the total mass of the plates is placed over the first of these plates with a buffer layer of inert granular material which is at least half the driver plate thickness between the driver plate and the first plate. Over the driver plate a layer of explosive is placed. The plates are metallurgically bonded by progressively propelling the plates together against a restraining means by detonating the explosive in a direction parallel to the plates at a velocity of less than 120% of the velocity of sound in the
plate with the lowest sonic velocity. The thickness of the buffer layer is sufficient to prevent welding of the driver plate to the first plate. Metal composites with fly ash incorporated therein and a process for producing the same Pond, R.B. (Westminster, MD, USA) US Pat 4 888 054 (19 December 1989) A metal-matrix material is mixed with fly ash to produce a homogeneous mixture which is heated and formed to produce a metal-matrix composite. Ceramic-ceramic composite material and production method Davidovits, N., Davidovits, M. and Davidovits, J. (Roanne, Pont Ste Maxence and Saint Quentin, France) US Pat 4 888 311 (19 Decem bet 1989) The composite ceramic-ceramic material has 30-430 parts by weight of reinforcing ceramic fibres impregnated with a mineral polymer of alkaline polysilicate and alkaline polysialate and a filler with dimensions lower than 5 p.m. The filler is selected from silica dust, alumina dust and micronized mica such that the mole ratios of oxides in the mixture of the mineral polymer and the filler are M20/Si02=0.100.95; SIO:,/A!203=2.50-6.00 and M20/ A1203=0.25-5.70. The mixture of the ceramic matrix and the impregnated fibres is hardened by hydrothermai polycondensation at temperatures between 20-120°C to form the ceramic-ceramic composite. Process of producing titanium composite having a coil-shaped skeletal structure on the surface thereof Shimamune, T. and Hosonuma, M. (Permelec Electrode Ltd, Kanagawa, Japan) US Pat 4 889685 (26 December 1989) Titanium or titanium alloy coils are placed on the surface of a titanium or titanium alloy substrate and are coated with a composition which is a mixture of titanium or titanium alloy powder with a binder so the coils and the substrate are firmly attached to each other. To produce the finished product the assembly is sintered by heating either in vacuo or in an inert atmosphere. Carbon-fibre-reinforced metallic material and method of producing the same Fukizawa, K., Ohshima, T. and Hata, T. (Honda Giken Kogyo Kabushiki Kaisha, Tokyo, Japan) US Pat 4 889 774 (26 December 1989) A mixture of carbon fibres and a metal powder is formed into a shaped article which is pre-heated in a non-oxidizing atmosphere and then exposed to the ambient atmosphere so that the metal oxidizes and generates heat, thus suppressing the oxidation of the carbon fibres. The article is then filled with a molten metal which is subsequently solidified.
COMPOSITES. JULY 1991