High-strength aluminum alloy extruded material that exhibits excellent formability and method for producing the same

Abstract

An aluminum alloy extruded material exhibits excellent hardenability that ensures that high strength can be obtained by air-cooling immediately after extrusion and artificial aging, and exhibits excellent formability (e.g., press formability). An aluminum alloy includes 0.30 to 1.00 mass % of Mg, 0.6 to 1.40 mass % of Si, 0.10 to 0.40 mass % of Fe, 0.10 to 0.40 mass % of Cu, 0.005 to 0.1 mass % of Ti, and 0.3 mass % or less of Mn, with the balance being aluminum and unavoidable impurities, the aluminum alloy having a stoichiometric Mg 2 Si content of 0.60 to 1.30 mass % and an excess Si content of 0.30 to 1.00 mass %.

What is claimed is: 
     
         1 . An aluminum alloy that is used to produce a high-strength aluminum alloy extruded material that exhibits excellent formability, the aluminum alloy consisting of 0.30 to 1.00 mass % of Mg, 0.6 to 1.40 mass % of Si, 0.10 to 0.40 mass % of Fe, 0.10 to 0.40 mass % of Cu, 0.005 to 0.1 mass % of Ti, and 0.3 mass % or less of Mn, with the balance being aluminum and unavoidable impurities, the aluminum alloy having a stoichiometric Mg 2 Si content of 0.60 to 1.30 mass % and an excess Si content of 0.30 to 1.00 mass %. 
     
     
         2 . A high-strength aluminum alloy extruded material that exhibits excellent formability, the extruded material being produced using the aluminum alloy as defined in  claim 1 , the extruded material having a structure in which crystal grains having an aspect ratio of 4.0 or more have an average grain size of 100 μm or less. 
     
     
         3 . An aluminum alloy that is used to produce a high-strength aluminum alloy extruded material that exhibits excellent formability, the aluminum alloy consisting of 0.30 to 1.00 mass % of Mg, 0.6 to 1.40 mass % of Si, 0.10 to 0.40 mass % of Fe, 0.10 to 0.40 mass % of Cu, 0.005 to 0.1 mass % of Ti, 0.3 mass % or less of Mn, 0.01 to 2.0 mass% of Zn, and 0.10 mass % or less of Zr, with the balance being aluminum and unavoidable impurities, the aluminum alloy having a stoichiometric Mg 2 Si content of 0.60 to 1.30 mass % and an excess Si content of 0.30 to 1.00 mass %. 
     
     
         4 . A high-strength aluminum alloy extruded material that exhibits excellent formability, the extruded material being produced using the aluminum alloy as defined in  claim 3 , the extruded material having a structure in which crystal grains having an aspect ratio of 4.0 or more have an average grain size of 100 μm or less. 
     
     
         5 . A method for producing a high-strength aluminum alloy extruded material that exhibits excellent formability, the method comprising extruding a billet of the aluminum alloy as defined in  claim 1  to obtain an extruded product, air-cooling the extruded product immediately after the extrusion at an average cooling rate of 50 to 150° C./min, and subjecting the cooled extruded product to artificial aging. 
     
     
         6 . A method for producing a high-strength aluminum alloy extruded material that exhibits excellent formability, the method comprising extruding a billet of the aluminum alloy as defined in  claim 3  to obtain an extruded product, air-cooling the extruded product immediately after the extrusion at an average cooling rate of 50 to 150° C./min, and subjecting the cooled extruded product to artificial aging.