| 摘要 |
1507001 Turbine blades formed of porous material MOTOREN-UND TURBINEN UNION MUNCHEN GmbH 27 Jan 1976 [28 Jan 1975] 03129/76 Heading FIT An article such as a turbine blade comprises a central core 5 and an outer portion 3 surrounding the core, the outer portion being supported by the core by means of radial webs 4, the outer portion being porous to allow cooling fluid to permeate outwardly therethrough. Cooling fluid is supplied to the blade root as shown by arrows 7 the cooling fluid passing into passages 6 formed between the ribs 4, the central core and the outer portion and then permeating through the outer portion. The blade is formed by making a body as shown in Fig. 2 which is a negative of the final blade comprising an outer portion 3a formed of an aerated porous ceramic material such as aluminium oxide and having ribs 4a on its inner surface, the ribs 4a being of the same ceramic material but non-porous and forming the passages 6 of the final blade. The body is placed in a casting mould which defines the final shape of the blade and the blade material in liquid form such as molten metal is then poured into the mould, the mould being subject to vacuum whereby the molten metal fills the pores of the porous body. The body material is then dissolved by chemical means and removed leaving the finished blade. The porous body may be filled with a fluid which is allowed to solidify, the mould being then formed around the filled body; the body filling is then made fluid and removed from the body after which the final blade material is introduced.
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