To provide an aluminum alloy sheet for magnetic disk substrate, having smooth surface, practically free from difference in level in the boundary between a core material and a cladding material, and capable of recycling generated scrap as a raw material for cladding material.
In the Al alloy clad sheet for magnetic disk substrate, formed by cladding one side or both sides of a core material with a cladding material, the cladding material has a composition containing, by weight, 2.0-6.0% Mg, 0.01-0.15% Cu, 0.05-2.0% Zn, and one or ≥2 elements among 0.01-0.40% Mn, 0.01-0.30% Cr, 0.01-0.12% Zr, and 0.01-0.05% Ni, also containing, as impurity elements, ≤0.05% Si, ≤0.05% Fe, ≤0.02% Ti, and ≤0.02% each of other impurity elements, and having the balance Al. The core material has a composition consisting of Mg, Cu, Zn, one or Z2 elements among Mn, Cr, Zr, and Ni, and the balance Al with inevitable impurities. Moreover, respective ratios of contents of Mg, Cu, and Zn between the cladding material and the core material (cladding material/core material) are regulated to 0.7-1.3, respectively, and also respective ratios of contents of Cr, Mn, Zr, and Ni between the cladding material and the core material are regulated to ≤1.3, respectively, and further, respective ratios of contents of Si and Fe between the cladding material and the core material are regulated to ≤1.0, respectively.
TOTSUGI YOICHIRO
KUBO YOSHINARI
