| 摘要 |
<p>PURPOSE:To manufacture a preform free from the disorder of short-fiber orientation, by subjecting a mixture of a short-fiber reinforcement and a molding auxiliary to injection molding to form a preform in which the short fibers are unidirectionally oriented and then bringing this preform into contact with a liquid in the supercritical state to remove the molding auxiliary. CONSTITUTION:A molding auxiliary (higher fatty acid, higher alcohol, etc.) is added by <=about 200% to a short-fiber reinforcement (consisting of silica, alumina, etc., and having <=about 10mm length), by which a preform in which the short fibers are unidirectionally oriented is prepared by means of injection molding or extrusion forming. Subsequently, this preform is brought into contact with a fluid of a material (carbon dioxide, ethane, etc.) forming a fluid in the supercritical state for about 2-5hr, by which the molding auxiliary is removed so that it remains by about 10-40wt.% based on the preform. By this method, the preform free from the disorder of short-fiber orientation and also free of cracking, bulge, etc., can be obtained. Further, the molding auxiliary remaining in the preform is removed in a preform-preheating stage before casting at the time of manufacturing a metallic composite material.</p> |
