Aluminum Alloy Combining High Strength, Elongation and Extrudability

Abstract

An aluminum alloy includes, in weight percent, 0.70-0.85 Si, 0.14-0.25 Fe, 0.25-0.35 Cu, 0.05 max Mn, 0.75-0.90 Mg, 0.12-0.18 Cr, 0.05 max Zn, and 0.04 max Ti, the balance being aluminum and unavoidable impurities. The alloy may be suitable for extruding, and may be formed into an extruded alloy product.

What is claimed is: 
     
         1 . An aluminum alloy comprising, in weight percent, 0.70-0.85 Si, 0.14-0.25 Fe, 0.25-0.35 Cu, 0.05 max Mn, 0.75-0.90 Mg, 0.12-0.18 Cr, 0.05 max Zn, and 0.04 max Ti, the balance being aluminum and unavoidable impurities. 
     
     
         2 . The alloy of  claim 1 , wherein the unavoidable impurities may each be present at a maximum weight percent of 0.05, and the maximum total weight percent of the unavoidable impurities is 0.15. 
     
     
         3 . The alloy of  claim 1 , wherein the Mn content is 0.03 max weight percent. 
     
     
         4 . The alloy of  claim 1 , wherein the alloy is extruded, and wherein less than about 20% of a cross section of the extruded alloy has undergone recrystallization over at least a portion of a length of the extruded alloy. 
     
     
         5 . The alloy of  claim 4 , wherein less than about 10% of the cross section has undergone recrystallization over the at least a portion of the length of the extruded alloy. 
     
     
         6 . The alloy of  claim 1 , wherein the alloy is extruded, and wherein less than about 20% of a cross section of the extruded alloy has undergone recrystallization over an entire length of the extruded alloy. 
     
     
         7 . The alloy of  claim 6 , wherein less than about 10% of the cross section has undergone recrystallization over the entire length of the extruded alloy. 
     
     
         8 . The alloy of  claim 1 , wherein the alloy has a tensile yield strength of at least about 310 MPa. 
     
     
         9 . The alloy of  claim 1 , wherein the alloy has a tensile elongation of at least about 12%. 
     
     
         10 . The alloy of  claim 1 , wherein the alloy has a fine Cr dispersoid distribution. 
     
     
         11 . The alloy of  claim 1 , wherein the alloy is extruded, wherein the extruded alloy has a substantially non-recrystallized microstructure, and wherein the alloy has a tensile yield strength of at least about 310 MPa and a tensile elongation of at least about 12%. 
     
     
         12 . An extruded aluminum alloy product formed of an aluminum alloy comprising, in weight percent, 0.70-0.85 Si, 0.14-0.25 Fe, 0.25-0.35 Cu, 0.05 max Mn, 0.75-0.90 Mg, 0.12-0.18 Cr, 0.05 max Zn, and 0.04 max Ti, the balance being aluminum and unavoidable impurities, wherein the unavoidable impurities may each be present at a maximum weight percent of 0.05, and the maximum total weight percent of the unavoidable impurities is 0.15, wherein the extruded aluminum alloy product is homogenized prior to extrusion, and wherein the extruded aluminum alloy product has a substantially non-recrystallized microstructure, and wherein the extruded aluminum alloy product has a tensile yield strength of at least about 310 MPa and a tensile elongation of at least about 12%. 
     
     
         13 . The extruded aluminum alloy product of  claim 12 , wherein less than about 20% of a cross section of the extruded aluminum alloy product has undergone recrystallization over at least a portion of a length of the extruded aluminum alloy product. 
     
     
         14 . The extruded aluminum alloy product of  claim 13 , wherein less than about 10% of the cross section has undergone recrystallization over the at least a portion of the length of the extruded aluminum alloy product. 
     
     
         15 . The extruded aluminum alloy product of  claim 12 , wherein less than about 20% of a cross section of the extruded aluminum alloy product has undergone recrystallization over the entire length of the extruded aluminum alloy product. 
     
     
         16 . The extruded aluminum alloy product of  claim 15 , wherein less than about 10% of the cross section has undergone recrystallization over the entire length of the extruded aluminum alloy product. 
     
     
         17 . The extruded aluminum alloy product of  claim 12 , wherein the extruded aluminum alloy product has a minimum cross-sectional thickness greater than 6.30 mm. 
     
     
         18 . A method of forming an extruded product comprising:
 extruding an aluminum alloy having a composition, in weight percent, 0.70-0.85 Si, 0.14-0.25 Fe, 0.25-0.35 Cu, 0.05 max Mn, 0.75-0.90 Mg, 0.12-0.18 Cr, 0.05 max Zn, and 0.04 max Ti, the balance being aluminum and unavoidable impurities; and   quenching the alloy after extruding at a rate of at least 10° C./sec.   
     
     
         19 . The method of  claim 18 , wherein the extrusion is performed at an extrusion ratio of less than about 40/1, and the extruded product has a minimum cross-sectional thickness of at least 6.30 mm, and wherein less than about 20% of a cross section of the extruded product has undergone recrystallization over at least a portion of a length of the extruded product, and wherein the extruded product has a tensile yield strength of at least about 310 MPa and a tensile elongation of at least about 12%. 
     
     
         20 . The method of  claim 18 , further comprising homogenizing the alloy prior to extruding. 
     
     
         21 . The method of  claim 18 , wherein the quenching comprises press quenching performed by using water mist, spray or quench bath. 
     
     
         22 . The method of  claim 18 , further comprising artificially aging the alloy after quenching, wherein the artificial aging is carried out for 2-24 hours at an aging temperature of 160-200° C. 
     
     
         23 . The method of  claim 18 , wherein less than about 20% of a cross section of the extruded product has undergone recrystallization over at least a portion of a length of the extruded product. 
     
     
         24 . The method of  claim 23 , wherein less than about 10% of the cross section has undergone recrystallization over the at least a portion of the length of the extruded product. 
     
     
         25 . The method of  claim 18 , wherein the extruded product has a tensile yield strength of at least about 310 MPa and a tensile elongation of at least about 12%. 
     
     
         26 . The method of  claim 18 , wherein the alloy is extruded to a minimum thickness of at least 6.30 mm. 
     
     
         27 . The method of  claim 18 , wherein the extrusion is performed at an extrusion ratio of less than about 40/1. 
     
     
         28 . The method of  claim 18 , wherein the extrusion is performed with an extrusion strain of less than about 3.7. 
     
     
         29 . The method of  claim 18 , wherein the quenching is at a rate of at least 50° C./sec.