Abstract: A method is described for the manufacture of articles in defect-immunized materials in which the defects are eliminated, or broken up and oriented in such manner as to minimize their harmful effects on the article.Referring to FIG. 1e, a rotor disc for a gas turbine engine is formed to an approximate shape by stacking together "sticks" 5 of material in an evacuated container and bonding them together by a hot isostatic pressing process. The "sticks" 5 are produced by extruding a starting body, for example, of powder material, to produce an elongation of up to twenty times and then cutting them to the appropriate length. By this means any non-metallic inclusions in the powder are broken up, inspection of the sticks and rejection of defective ones becomes easier, and the sticks can be oriented so that the effects of any remaining defects can be minimized.

Abstract: A method is described for the manufacture of articles in defect immunized materials in which the defects are eliminated, or broken up and oriented in such manner as to minimize their harmful effects on the article. Referring to FIG. 1e, a rotor disc for a gas turbine engine is formed to an approximate shape by stacking together "sticks" 5 of material in an evacuated container and bonding them together by a hot isostatic pressing process. The "sticks" 5 are produced by extruding a starting body, for example, of powder material, to produce an elongation of up to twenty times and then cutting them to the appropriate length. By this means any non-metallic inclusions in the powder are broken up, inspection of the sticks and rejection of defective ones becomes easier, and the sticks can be oriented so that the effects of any remaining defects can be minimized.

Abstract: It is known to apply coatings which have desired characteristics, e.g., wear resistance, thermal barrier capabilities anti-oxidation, to articles the material of which does not have the desired characteristic, wherein the coating is applied directly to the article. Some article materials, e.g. titanium are highly reactive which immediately obviates several known methods of applying coatings. The invention uses a member (12) which would normally be preformed to mate with the article surface to be coated. The member (12) is manufactured from cheap, non-reactive material, as a base to which the coating (14) is applied by the most suitable of any of the known means. The member (12) is then placed against the article with the coating (14) therebetween and the whole hot isostatically pressed. The member (12) is afterwards removed, e.g. by machining or etching.

Abstract: The invention is concerned with the problem of joining ceramic components to metal components.A composite ceramic-metal component is proposed, e.g. a rotor disc for a gas turbine engine (see FIG. 2), in which the main body of the component is made from a ceramic, e.g. Silicon Nitride, but the areas at which attachment is to be made to a metal component is formed from metal compacted onto the ceramic by a hot isostatic pressing process.The method of manufacture described is to form a ceramic core with holes appropriately positioned in it where a connection is to be made to another component, surround the core with a powdered metal, e.g. a Nickel-based superalloy, ensuring that the holes also fill with powder, compacting the powder by hot isostatic pressing, and then machining away unwanted metal.