High-Strength Aluminum Alloy Extruded Material That Exhibits Excellent Formability And Method For Producing The Same

Abstract

An aluminum alloy is provided that is used to produce a high-strength aluminum alloy extruded material that exhibits excellent formability. The aluminum alloy consists 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 Mg2Si 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, 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 %. 
     
     
         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 . 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.