| 摘要 |
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.
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