Rolled aluminum alloy adapted for superplastic forming and method for making

A rolled aluminum alloy adapted for superplastic forming, consisting essentially of, in % by weight,

• 2.0 to 8.0% of Mg,
• 0.3 to 1.5% of Mn,
• 0.0001 to 0.01% of Be,
• at least one member selected from the group consisting of 0.05 to 0.3% of Cr, 0.05 to 0.3% of V, and 0.05 to 0.3% of Zr,
• less than 0.2% of Fe and less than 0.1% of Si as impurities, and
• the balance of Al,
• wherein intermetallic compounds have a size of up to 20 .mu.m, and the content of hydrogen present is up to 0.35 cc per 100 grams of the alloy.

A rolled aluminum alloy adapted for superplastic forming, consisting essentially of, in % by weight,

• 2.0 to 8.0% of Mg,
• 0.3 to 1.5% of Mn,
• 0.0001 to 0.01% of Be,
• 0.005 to 0.15% of Ti alone or in combination with 0.0001 to 0.05% by weight of B for grain refinement,
• less than 0.2% of Fe and less than 0.1% of Si as impurities, and
• the balance of Al,
• wherein intermetallic compounds have a size of up to 20 .mu.m, and the content of hydrogen present is up to 0.35 cc per 100 grams of the alloy.

A rolled aluminum alloy adapted for superplastic forming, consisting essentially of, in % by weight,

• 2.0 to 8.0% of Mg,
• 0.3 to 1.5% of Mn,
• 0.0001 to 0.01% of Be,
• at least one member selected from the group consisting of 0.05 to 0.3% of Cr, 0.05 to 0.3% of V, and 0.05 to 0.3% of Zr,
• 0.005 to 0.15% of Ti alone or in combination with 0.0001 to 0.05% by weight of B for grain refinement,
• less than 0.2% of Fe and less than 0.1% of Si as impurities, and
• the balance of Al,
• wherein intermetallic compounds have a size of up to 20 .mu.m, and the content of hydrogen present is up to 0.35 cc per 100 grams of the alloy.

A rolled aluminum alloy adapted for superplastic forming and exhibiting grey to black color after anodization, consisting essentially of, in % by weight,

• 2.0 to 8.0% of Mg,
• 0.3 to 1.5% of Mn,
• 0.0001 to 0.01% of Be,
• 0.005 to 0.15% of Ti alone or in combination with 0.0001 to 0.05% by weight of B for grain refinement,
• less than 0.2% of Fe and less than 0.1% of Si as impurities, and
• the balance of Al,
• wherein intermetallic compounds have a size of up to 20 .mu.m, manganese base precipitates have a size of at least 0.05 .mu.m, the amount of Si in entire precipitates is up to 0.07% by weight based on the total weight of the rolled alloy, and the content of hydrogen present is up to 0.35 cc per 100 grams of the alloy.

A rolled aluminum alloy adapted for superplastic forming and exhibiting grey to black color after anodization, consisting essentially of, in % by weight,

• 2.0 to 8.0% of Mg,
• 0.3 to 1.5% of Mn,
• 0.0001 to 0.01% of Be,
• at least one member selected from the group consisting of 0.05 to 0.3% of Cr, 0.05 to 0.3% of V, and 0.05 to 0.3% of Zr,
• 0.005 to 0.15% of Ti alone or in combination with 0.0001 to 0.05% by weight of B for grain refinement,
• less than 0.2% of Fe and less than 0.1% of Si as impurities, and
• the balance of Al,
• wherein intermetallic compounds have a size of up to 20 .mu.m, manganese base precipitates have a size of at least 0.05 .mu.m, the amount of Si in entire precipitates is up to 0.07% by weight based on the total weight of the rolled alloy, and the content of hydrogen present is up to 0.35 cc per 100 grams of the alloy.

A method for preparing a rolled aluminum alloy adapted for superplastic forming and exhibiting grey to black color after anodization, comprising the steps of:

• forming an alloy consisting essentially of, in % by weight, 2.0 to 8.0% of Mg, 0.3 to 1.5% of Mn, 0.0001 to 0.01% of Be, 0.005 to 0.15% of Ti alone or in combination with 0.0001 to 0.05% by weight of B for grain refinement, less than 0.2% of Fe and less than 0.1% of Si as impurities, and the balance of Al, by melting and semi-continuous casting,
• removing coarse cell layers from the surfaces of the cast ingot by scalping,
• heating the ingot at a temperature of 430.degree.0 to 560.degree. C. for 1/2 to 24 hours,
• hot rolling and then cold rolling the material into a strip of a predetermined thickness, the cold rolling step including final cold rolling to a draft of at least 30%.

A method for preparing a rolled aluminum alloy adapted for superplastic forming exhibiting grey to black color after anodization, comprising the steps of:

• forming an alloy consisting essentially of, in % by weight, 2.0 to 8.0% of Mg, 0.3 to 1.5% of Mn, 0.0001 to 0.01% of Be, at least one member selected from the group consisting of 0.05 to 0.3% of Cr, 0.05 to 0.3% of V, and 0.05 to 0.3% of Zr, 0.005 to 0.15% of Ti alone or in combination with 0.0001 to 0.05% by weight of B for grain refinement, less than 0.2% of Fe and less than 0.1% of Si as impurities, and the balance of Al, by melting and semicontinuous casting,
• removing coarse cell layers from the surfaces of the cast ingot by scalping,
• heating the cast ingot at a temperature of 430.degree.0 to 560.degree. C. for 1/2 to 24 hours,
• hot rolling and then cold rolling the material into a strip of a predetermined thickness, the cold rolling step including final cold rolling to a draft of at least 30%.