Abstract: A thixocast casting material is formed of an Fe—C—Si based alloy in which an angle endothermic section due to the melting of a eutectic crystal exists in a latent heat distribution curve and has a eutectic crystal amount Ec in a range of 10% by weight<Ec<50% by weight. This composition comprises 1.8% by weight≦C≦2.5% by weight of carbon, 1.4% by weight≦Si≦3% by weight if silicon and a balance of Fe including inevitable impurities.

Abstract: A thixocast casting material is formed of an Fe--C--Si based alloy in which an angle endothermic section due to the melting of a eutectic crystal exists in a latent heat distribution curve and has a eutectic crystal amount Ec in a range of 10% by weight <Ec<50% by weight. This composition comprises 1.8% by weight .ltoreq.C.ltoreq.2.5% by weight of carbon, 1.4% by weight .ltoreq.Si.ltoreq.3% by weight of silicon and a balance of Fe including inevitable impurities.

Abstract: In a thixocasting process, the following steps are used: a step of subjecting, to a heating treatment, an Al-Si based alloy material having a hypo eutectic crystal composition and a characteristic that a first angled endothermic section appearing due to the melting of a eutectic crystal and a second angled endothermic section appearing due to the melting of a component having a melting point higher than a eutectic point exist in a differential calorimetric curve, thereby preparing a semi-molten Al-Si based alloy material having solid and liquid phases coexisting therein; a step of pouring the semi-molten Al-Si based alloy material into a cavity in a casting mold under pressure; and a step of solidifying the semi-molten Al-Si based alloy material under pressure. When the temperature of a rise-start point in the first angled endothermic section is represented by T.sub.1, and the temperature of a drop-end point the first angled endothermic sections is represented by T.sub.

Abstract: Solid and liquid phases coexist in a semi-molten casting material. A plurality of composite-solid phases having liquid and solid phase regions and a plurality of single-solid phases exist as the solid phases in a mixed state in an outer layer portion of the semi-molten casting material. If the sectional area of the solid phase region is represented by A, and the sectional area of the solid phase region is represented by B in one of the composite-solid phases, the liquid phase enclosure rate P of the composite-solid phase is defined as being represented by P={B/(A+B)}.times.100 (%). The liquid phase enclosure rate P of the single-solid phase is equal to 0 (%). When two groups are selected from a class of the solid phases, for example, by first and second straight lines so as to include a plurality of the solid phases, average values M.sub.1 and M.sub.2 of liquid phase enclosure rates of, for example, six solid phases in each of the first and second groups are represented by M.sub.1 =(P.sub.1 +P.sub.2 - - - +P.

Abstract: A differential thermal analysis thermograph for a thixocasting aluminum alloy material is such that, a relationship, E.sub.1 >E.sub.2, is established between a peak value E.sub.1 of a first angled endothermic section generated by eutectic melting and a peak value E.sub.2 of a second angled endothermic section generated by melting of an element having a melting point higher than the eutectic point. Thus, a liquid phase produced by the eutectic melting has a large latent heat due to the fact that the peak value E.sub.1 of the first angled endothermic section is larger than the peak value E.sub.2 of the second angled endothermic section in a semi-molten eutectic aluminum alloy material derived from the thixocasting aluminum alloy material. As a result, in a solidification step of the thixocasting process, a liquid phase produced by the eutectic melting is sufficiently fed around a solid phase in response to the solidification and shrinkage of the solid phase, and then solidified.

Abstract: The aluminum alloy of the invention has excellent fatigue strength, high rigidity, and low thermal expansion coefficient, and is suitable for rotating components such as conrods in an internal combustion engine. The aluminum alloy is an Al-Si alloy which contains 7.0-12.0% wt. Si, 3.0-6.0 % wt. Cu, 0.20-1.0% wt. Mg, 0.30-1.5% wt. Mn, 0.40-2.0% wt. Ti+V, 0.05-0.5% wt. Zr, and the remainder Al and being inevitable impurities and which contains a dispersed intermetallic compound of average particle size of 0.5 m or less and containing Ti, V, and Zr. The alloy is preferably manufactured by the rapidly solidifying powder metallurgy process, or by the spray-forming process. By selecting a work-hardening exponent of 0.20 or less, the thread rolling workability is improved.

Abstract: A process for producing an aluminum-based alloy cast product, includes the steps of: preparing a casting material having an aluminum-based hypo-eutectic alloy composition with solid and liquid phases coexisting therein; and subjecting the casting material to a casting under pressure. At this casting step, the casting material is passed through a gate in a casting mold under conditions of a viscosity .mu. in a range of 0.1 Pa.multidot.sec.ltoreq..mu..ltoreq.2,000 Pa.multidot.sec and a Reynolds number in a range of Re.ltoreq.1,500.

Abstract: A valve spring retainer for a valve operating mechanism for an internal combustion engine comprises a matrix formed from a quenched and solidified aluminum alloy powder, and a hard grain dispersed in said matrix. The hard grain is at least one selected from the group consisting of grains of Al.sub.2 O.sub.3, SiC, Si.sub.3 N.sub.4, ZrO.sub.2, SiO.sub.2, TiO.sub.2, Al.sub.2 O.sub.3 -SiO.sub.2 and metal Si. The amount of hard grain added is in a range of 0.5% to 20% by weight, and the area rate of said hard grain is in a range of from 1% to 6%.

Abstract: Al-alloy containing Si, Fe, Cu and Mg and at least one kind of Mn and Co in the basic composition range of 8.0.ltoreq.Si.ltoreq.30.0 wt. %, 2.0.ltoreq.Fe.ltoreq.33.0 wt. %, 0.8.ltoreq.Cu.ltoreq.7.5 wt. %, 0.3.ltoreq.Mg.ltoreq.3.5 wt. %, 0.5.ltoreq.Mn.ltoreq.5.0 wt. % and 0.5.ltoreq.Co.ltoreq.3.0 wt. %, are provided in a powder state. A sindered member formed of these Al-alloys has a high strength and reveals excellent heat-resistivity and stress corrosion cracking resistivity. A structural member made of the sintered all-alloy is manufactured through the steps of subjecting a powder press-shaped body formed at a temperature of 350.degree. C. or lower and at a pressure of 1.5.about.5.0 ton/cm.sup.2 to hot extrusion working at a temperature of 300.degree..about.400.degree. C. to form a raw material for forging, and then forge shaping the raw material at a temperature of 300.degree..about.495.degree. C.

Abstract: This invention relates to a method of manufacturing a structural member made of a sintered Al alloy having heat resistance and high strength. A powder is used having a composition which makes it difficult to perform hot forging, i.e. 8.0 to 30.0 wt. % of Si, 0.8 to 7.5 wt. % of Cu, 0.3 to 3.5 wt. % of Mg, 2.0 to 10.0 wt. % of Fe, 0.5 to 5.0 wt. % of Mn, and a balance of Al. After being subjected to press-forming, this Al alloy powder is subjected to hot extrusion at a temperature of 300.degree. to 450.degree. C., the extruded product is heated with electric resistance heating by electric current which is passed therethrough and subjected to forging at a temperature of 300.degree. to 495.degree. C. According to this method, a structural member made of a sintered Al alloy having heat resistance and high strength and having the aforementioned powder composition can be easily obtained without cracking.

Abstract: An Al-alloy containing Si, Fe, Cu and Mg and at least one of Mn and Co in the basic composition range of 8.0.ltoreq.Si.ltoreq.30.0 wt. %, 2.0.ltoreq.Fe.ltoreq.33.0 wt. %, 0.8.ltoreq.Cu.ltoreq.7.5 wt. %, 0.3.ltoreq.Mg.ltoreq.3.5 wt. %, 0.5.ltoreq.Mn.ltoreq.5.0 wt. % and/or 0.5.ltoreq.Co.ltoreq.3.0 wt. %, provided in a powder state. A sindered member formed of these Al-alloys displays high strength, excellent heat-resistivity and stress corrosion cracking resistivity. A structural member made of the sintered Al-alloy is manufactured through the steps of subjecting a powder press-shaped body formed at a temperature of 350.degree. C. or lower and at a pressure of 1,5.about.5.0 ton/cm to hot extrusion working at a temperature of 300.degree..about.400.degree. C. to form a raw material for forging, and then forge shaping the raw material at a temperature of 300.degree..about.495.degree. C.

Abstract: A high strength structural member made of Al-alloy is essentially formed of a sintered body of Al-alloy powder containing Si and Fe in the proportion of 10.ltoreq.Si.ltoreq.30 wt. % and 4.ltoreq.Fe.ltoreq.33 wt. %, and the surface layer of the sintered body is subjected to remelting-solidifying treatment with a high-density energy source such as a laser beam, a plasma arc, a TIG arc, etc. In the treated surface layer of the sintered body, grain sizes of Si crystal grains and precipitated intermetallic compound are reduced to 1 .mu.m or smaller, whereas in the base portion of the sintered body that is not subjected to the remelting-solidifying treatment, grain sizes of Si crystal grains and precipitated intermetallic compound are kept 10 .mu.m or smaller.