Abstract: An Al-base alloy prepared by hot-working a mixture of an Al alloy powder and dan Ni powder to join the powders and having a structure wherein Ni--Al intermetallic compounds are dispersed. The powder mixture can be hot-worked in the solid-phase temperature range, liquid phase temperature range or solid-liquid phase mixture temperature range of the Al alloy. A dispersion strengthening powder can be further admixed with the mixture of Al alloy powder and Ni powder.

Abstract: A filter for molten metal having a high melting point is in the form of a net woven of glass yarns formed by twisting a multiplicity of glass fibers together. The glass fibers contain at least 75 wt. % of SiO.sub.2 and are thermally cured at a thermal shrinkage of 2.5 to 15%. The thermal shrinkage is expressed by (l-l')/.times.100 % wherein l is the length of the fiber before the thermal cure, and l' is the length of the fiber as thermally cured.

Abstract: A chill preventing arrangement is used in a metal mold employed in centrifugal casting. The metal mold is provided, at its spigot portion, with an end plate which has a central opening smaller in diameter than the internal diameter of the metal mold main body and which includes a metallic base plate, an intermediate layer of metallic alloy formed by flame or plasma spraying on a surface of the metallic base plate contacting the molten metal for casting, and a coating of ceramic material more than 0.7 mm thick formed on the intermediate layer by flame or plasma spraying for preventing chill formation at the corresponding end portions of tubular castings.