Abstract: A method includes: preparing a molten aluminum alloy consisting of 0.3-0.8 mass % Mg, 0.5-1.2 mass % Si, 0.3 mass % or more excess Si relative to the Mg2Si stoichiometric composition, 0.05-0.4 mass % Cu, 0.2-0.4 mass % Mn, 0.1-0.3 mass % Cr, 0.2 mass % or less Fe, 0.2 mass % or less Zr, and 0.005-0.1 mass % Ti, with the balance being aluminum and unavoidable impurities; casting the alloy into a billet at a speed of 80 mm/min or more and a cooling rate of 15° C./sec or more; extruding the billet into an extruded product; water cooling the product immediately after extrusion at 500° C./min or more; and artificially aging the product, thereby yielding an extruded product with fatigue strength of 140 MPa or more, fatigue ratio of 0.45 or more, an interval between striations on a fatigue fracture surface of 5.0 ?m or less, and a maximum length of Al—Fe—Si crystallized products of 10 ?m or less.

Abstract: A method includes: preparing a molten aluminum alloy consisting of 0.3-0.8 mass % Mg, 0.5-1.2 mass % Si, 0.3 mass % or more excess Si relative to the Mg2Si stoichiometric composition, 0.05-0.4 mass % Cu, 0.2-0.4 mass % Mn, 0.1-0.3 mass % Cr, 0.2 mass % or less Fe, 0.2 mass % or less Zr, and 0.005-0.1 mass % Ti, with the balance being aluminum and unavoidable impurities; casting the alloy into a billet at a speed of 80 mm/min or more and a cooling rate of 15° C./sec or more; extruding the billet into an extruded product; water cooling the product immediately after extrusion at 500° C./sec or more; and artificially aging the product, thereby yielding an extruded product with fatigue strength of 140 MPa or more, fatigue ratio of 0.45 or more, an interval between striations on a fatigue fracture surface of 5.0 ?m or less, and a maximum length of Al—Fe—Si crystallized products of 10 ?m or less.

Abstract: An aluminum alloy extruded product includes 0.3 to 0.8 mass % of Mg, 0.5 to 1.2 mass % of Si, 0.3 mass % or more of excess Si with respect to the Mg2Si stoichiometric composition, 0.05 to 0.4 mass % of Cu, 0.2 to 0.4 mass % of Mn, 0.1 to 0.3 mass % of Cr, 0.2 mass % or less of Fe, 0.2 mass % or less of Zr, and 0.005 to 0.1 mass % of Ti, with the balance being aluminum and unavoidable impurities, the aluminum alloy extruded product having a fatigue strength of 140 MPa or more, a fatigue ratio of 0.45 or more, and an interval between striations on a fatigue fracture surface of 5.0 ?m or less.

Abstract: An aluminum alloy material for forging obtained by a continuous casting process, the alloy comprising: a surface of which roughness is not more than Ra 35, and a segregation layer having 0.1 to 2 mm thickness and generated in the surface. The cast surface after continuous casting is smooth without peeling, a cast material can be forged without any treatment, and a segregation layer remains in a surface layer, thereby inhibiting coarsening of recrystallization grains and exhibiting superior toughness and strength.

Abstract: An aluminum alloy material for forging obtained by a continuous casting process, the alloy comprising: a surface of which roughness is not more than Ra 35, and a segregation layer having 0.1 to 2 mm thickness and generated in the surface. The cast surface after continuous casting is smooth without peeling, a cast material can be forged without any treatment, and a segregation layer remains in a surface layer, thereby inhibiting coarsening of recrystallization grains and exhibiting superior toughness and strength.

Abstract: A fiber-reinforced composite cylindrical form formed by winding up unidirectional prepreg sheets around a mandrel according to such four patterns as to set the fiber winding angles of the resulting layers thereof at 0.degree., 90.degree., 40.degree. to 50.degree., and -40.degree. to -50.degree. with the longer direction thereof, and then heat-curing said layers of said prepreg sheets.

Abstract: This invention is to provide a lightweight, inexpensive reflecting mirror. A reflecting layer is formed on the front surface of a carbon fiber-reinforced plastic substrate. An reflecting mirror includes a first substrate consisting of a carbon fiber-reinforced plastics, a reflecting layer formed on the front surface of the first substrate, a second substrate formed on the rear surface of the first substrate, an edge member formed at edges of the first and second substrates, and a foamed body filled in a space defined by the first and second substrates and the edge member. The second substrate and the edge member preferably consist of a carbon fiber-reinforced plastics.