Aluminum alloy sheet for forming and automobile member

Abstract

Provided is a 5xxx aluminum alloy sheet for forming, which sheet has low elongation anisotropy (in-plane anisotropy) and excellent press formability while having strength maintained at high level. This aluminum alloy sheet is an Al—Mg alloy sheet having a specific chemical composition. In the texture of the sheet, the orientation densities of Brass orientation and S orientation relative to a random orientation are controlled and minimized, where the orientation densities are expressed by orientation distribution functions. This allows the aluminum alloy sheet to have lower elongation anisotropy to thereby have better press formability.

1 . An aluminum alloy sheet comprising:
 Mg in a content of 3.5 to 5.5 mass %;   Mn in a content of 0.03 to 0.60 mass %;   Cu in a content of 0.001 to 0.50 mass %;   Zn in a content of 0.001 to 0.50 mass %,   Al and unavoidable impurities,   wherein orientation densities of Brass orientation and S orientation relative to a random orientation are each less than 5 in a texture of the aluminum alloy sheet, in a plane parallel to a sheet surface, where the plane is positioned at a depth half the thickness of the aluminum alloy sheet, and where the orientation densities are measured by SEM-EB SD analysis and are expressed by orientation distribution functions (ODFs).   
     
     
         2 . The aluminum alloy sheet according to  claim 1 ,
 wherein the orientation densities of the Brass orientation and the S orientation are each less than 2 in the texture of the aluminum alloy sheet.   
     
     
         3 . The aluminum alloy sheet according to  claim 1 ,
 wherein the aluminum alloy sheet has such elongation anisotropy that a JIS No. 5 test specimen sampled from the aluminum alloy sheet, when subjected to a tensile test at room temperature, has a difference in elongation of 2% or less between a tensile direction parallel to a sheet rolling direction and a tensile direction perpendicular to the sheet rolling direction.   
     
     
         4 . An automobile member formed from the aluminum alloy sheet according to  claim 1 . 
     
     
         5 . The aluminum alloy sheet according to  claim 2 ,
 wherein the aluminum alloy sheet has such elongation anisotropy that a JIS No. 5 test specimen sampled from the aluminum alloy sheet, when subjected to a tensile test at room temperature, has a difference in elongation of 2% or less between a tensile direction parallel to a sheet rolling direction and a tensile direction perpendicular to the sheet rolling direction.