High strength aluminum alloy sheet

Abstract

A high strength 6000-series aluminum alloy sheet improved with good bendability is provided. Amounts of solute Mg and solute Si are increased in a good balance, on the premise of not greatly changing the composition and the manufacturing condition of the aluminum alloy sheet, thereby promoting formation of Mg—Si clusters in a good balance between the number of Mg and Si atoms to increase the strength after BH without deteriorating the bendability even after natural aging.

What is claimed is: 
     
         1 . A high strength Al—Mg—Si alloy sheet comprising, based on mass %,
 0.6 to 2.0% of Mg, 
 0.6 to 2.0% of Si, 
 1.0% or less of Mn (not including 0%), and 
 0.5% or less of Fe (not including 0%) respectively, with the remainder consisting of Al and inevitable impurities, wherein both of a Mg content and a Si content separated in a solution by a residue extraction method with hot phenol are 0.6% or more as an amount of solute Mg and an amount of solute Si of the sheet, the sum of the amount of solute Mg and the amount of solute Si is 1.4% or more, and the ratio of the amount of solute Si to the amount of solute Mg (solute Si/solute Mg) is 0.8 to 1.2. 
 
     
     
         2 . The high strength aluminum alloy sheet according to  claim 1 , wherein
 the aluminum alloy sheet further comprises one or more of,   1.0% or less (not including 0%) of Cu,   0.3% or less (not including 0%) of Cr,   0.2% or less (not including 0%) of Zr,   0.2% or less (not including 0%) of V,   0.1% or less (not including 0%) of Ti,   0.5% or less (not including 0%) of Zn,   0.2% or less (not including 0%) of Ag, and   0.15% or less (not including 0%) of Sn.