Aluminum alloy sheet

Abstract

Provided is a 6000-series aluminum alloy sheet excellent in strength and bendability. The alloy sheet is an Al—Mg—Si aluminum alloy sheet including Mg: 0.5 to 1.3% by mass, and Si: 0.7 to 1.5% by mass; one or more elements selected from Mn: 0.05 to 0.5% by mass, Zr: 0.04 to 0.20% by mass, and Cr: 0.04 to 0.20% by mass; and Al and inevitable impurities as the remainder of the alloy sheet. Transition-element-based dispersed particles which are present on grain boundaries of the alloy sheet and which have a size of 0.05 μm or more have a number density of 0.001 nm −1 or less. The grain boundaries show a PFZ width of 60 nm or less after the aluminum alloy sheet is subjected to an artificial aging of holding the aluminum alloy sheet at 200 to 250° C. for 10 to 30 minutes.

1 . An Al—Mg—Si aluminum alloy sheet, comprising:
 Mg: 0.5 to 1.3% by mass; 
 Si: 0.7 to 1.5% by mass; 
 one or more elements selected from the group consisting of the following:
 Mn: 0.05 to 0.5% by mass, 
 Zr: 0.04 to 0.20% by mass, and 
 Cr: 0.04 to 0.20% by mass; and 
 
 Al and inevitable impurities, 
 wherein: 
 the aluminum alloy sheet has grains, and grain boundaries therebetween; 
 transition-element-based dispersed particles are present on the grain boundaries and have a size of 0.05 μm or more and have a number density of 0.001 nm −1  or less; and 
 the grain boundaries show a PFZ width of 60 nm or less after the aluminum alloy sheet is subjected to an artificial aging of holding the aluminum alloy sheet at 200 to 250° C. for 10 to 30 minutes. 
 
     
     
         2 . The aluminum alloy sheet according to  claim 1 , further comprising:
 Cu: more than 0% by mass, and 0.5% or less by mass.   
     
     
         3 . The aluminum alloy sheet according to  claim 1 , further comprising:
 Sc: 0.02 to 0.1% by mass.   
     
     
         4 . The aluminum alloy sheet according to  claim 2 , further comprising:
 Sc: 0.02 to 0.1% by mass.   
     
     
         5 . The aluminum alloy sheet according to  claim 1 , further comprising one or more elements selected from the group consisting of:
 Ag: 0.01 to 0.2% by mass, and   Sn: 0.001 to 0.1% by mass.   
     
     
         6 . The aluminum alloy sheet according to  claim 2 , further comprising one or more elements selected from the group consisting of:
 Ag: 0.01 to 0.2% by mass, and   Sn: 0.001 to 0.1% by mass.   
     
     
         7 . The aluminum alloy sheet according to  claim 3 , further comprising one or more elements selected from the group consisting of:
 Ag: 0.01 to 0.2% by mass, and   Sn: 0.001 to 0.1% by mass.   
     
     
         8 . The aluminum alloy sheet according to  claim 1 , showing a 0.2% yield strength of 250 MPa or more, and a VDA bending angle of 60° or more after the aluminum alloy sheet is subjected to the artificial aging of holding the aluminum alloy sheet at 200 to 250° C. for 10 to 30 minutes.