Al-Cu-Mg ALLOY SUITABLE FOR AEROSPACE APPLICATION

Abstract

An aluminium alloy wrought product having high strength and high fracture toughness and high resistance to intergranular corrosion. The alloy including in weight %: Cu 4.1-5.5%; Mg 0.30-1.6%; Mn 0.15-0.8%; Ti 0.03-0.4%; Cr 0.05-0.4%; Ag<0.7%; Zr<0.2%; Fe<0.20%, preferably <0.15%, more preferably <0.1%; Si<0.20%, preferably <0.15%, more preferably <0.1%; and the balance being aluminium and other impurities or incidental elements each <0.05%, total <0.15%.

1 . An aluminium alloy wrought product having high strength and high fracture toughness and high resistance to intergranular corrosion, said aluminium alloy wrought product made of an alloy comprising in weight %:  
     
       
         
               
               
               
             
                   
                   
               
                   
                   
               
                   
                 Cu 
                  4.1-5.5% 
               
                   
                 Mg 
                 0.30-1.6% 
               
                   
                 Mn 
                 0.15-0.8% 
               
                   
                 Ti 
                 0.03-0.4% 
               
                   
                 Cr 
                 0.05-0.4% 
               
                   
                 Ag 
                 <0.7% 
               
                   
                 Zr 
                 <0.2% 
               
                   
                 Fe 
                 <0.20% 
               
                   
                 Si 
                 <0.20%, 
               
                   
                   
               
                   
                   
               
           
              
              
             
             
              
              
              
              
              
              
              
              
              
              
              
             
          
         
       
     
     and the balance being aluminium and other impurities or incidental elements each <0.05%, total <0.15%.  
   
   
       2 . The aluminium alloy product according to  claim 1 , wherein Fe<0.15%.  
   
   
       3 . The aluminium alloy product according to  claim 1 , wherein Fe<0.1%.  
   
   
       4 . The aluminium alloy product according to  claim 1 , wherein Si<0.15%.  
   
   
       5 . The aluminium alloy product according to  claim 1 , wherein Si<0.1%.  
   
   
       6 . The aluminium alloy product according to  claim 1 , wherein 0.03%<Ti<0.3%.  
   
   
       7 . The aluminium alloy product according to  claim 1 , wherein 0.05%<Ti<0.2%.  
   
   
       8 . The aluminium alloy product according to  claim 1 , wherein 0.05%<Cr<0.3%.  
   
   
       9 . The aluminium alloy product according to  claim 1 , wherein 0.05%<Cr<0.15%.  
   
   
       10 . The aluminium alloy product according to  claim 1 , wherein 0.1%<Ti+Cr<0.4%.  
   
   
       11 . The aluminium alloy product according to  claim 1 , wherein 0.1%<Ti+Cr<0.3%.  
   
   
       12 . The aluminium alloy product according to  claim 1 , wherein 4.4%<Cu<5.5%.  
   
   
       13 . The aluminium alloy product according to  claim 1 , wherein 4.7%<Cu<5.3%.  
   
   
       14 . The aluminium alloy product according to  claim 1 , wherein 0.3%<Mg<1.2%.  
   
   
       15 . The aluminium alloy product according to  claim 1 , wherein 0.4%<Mg<0.75%.  
   
   
       16 . The aluminium alloy product according to  claim 1 , wherein 0.2%<Mn<0.5%.  
   
   
       17 . The aluminium alloy product according to  claim 1 , wherein Ag is present at the level of an impurity or incidental element.  
   
   
       18 . The aluminium alloy product according to  claim 17 , which is substantially free of Ag.  
   
   
       19 . The aluminium alloy product according to  claim 1 , wherein the product is in the T3x, T6x or T8x temper.  
   
   
       20 . The aluminium alloy product according to  claim 1 , wherein the product is in the form of a sheet, plate, forging or extrusion for use in an aerospace structure.  
   
   
       21 . The aluminium alloy product according to  claim 1 , wherein the product is in the form of a plate having a thickness in the range of 0.7 to 80 mm.  
   
   
       22 . A method for the manufacture of an aluminium alloy product having high strength and high fracture toughness and a high resistance to intergranular corrosion comprising the steps of: 
 a. casting an ingot having a composition of the alloy according to  claim 1;     b. homogenising and/or pre-heating the ingot after casting;    c. hot working the ingot into a pre-worked product by one of more methods selected from the group consisting of rolling, extruding and forging;    d. optionally reheating the pre-worked product and either    e. hot working and/or cold working to a desired work piece form;    f. solution heat treating said formed work piece at a temperature and time sufficient to place into solid solutions substantially all soluble constituents in the alloy;    g. quenching the solution heat treated work piece by one of spray quenching or immersion quenching in water or other quenching media;    h. optionally stretching or compressing of the quenched work piece;    i. naturally or artificially ageing the quenched and optional stretched or compressed work piece to achieve a desired temper.    
   
   
       23 . The method of manufacturing according to  claim 22 , wherein the aluminium alloy product is aged to a temper selected from the group comprising T3, T351, T39, T6, T651 and T87.  
   
   
       24 . The method of manufacturing according to  claim 22 , wherein the aluminium alloy product is processed to fuselage sheet.  
   
   
       25 . The method of manufacturing according to  claim 22 , wherein the aluminium alloy product is processed to fuselage sheet having a thickness of less then 30 mm.  
   
   
       26 . The method of manufacturing according to  claim 22 , wherein the aluminium alloy product is processed to lower wing plate.  
   
   
       27 . The method of manufacturing according to  claim 22 , wherein the aluminium alloy product is processed to upper wing plate.  
   
   
       28 . The method of manufacturing according to  claim 22 , wherein the aluminium alloy product is processed to an extruded product.  
   
   
       29 . The method of manufacturing according to  claim 22 , wherein the aluminium alloy product is processed to a forged product.  
   
   
       30 . The method of manufacturing according to  claim 22 , wherein the aluminium alloy product is processed to a thin plate having a thickness in the range of 15 to 40 mm.  
   
   
       31 . The method of manufacturing according to  claim 22 , wherein the aluminium alloy product is processed to a thick plate having a thickness of at most 300 mm.  
   
   
       32 . The method of manufacturing according to  claim 22 , comprising said reheating the pre-worked product.  
   
   
       33 . The method of manufacturing according to  claim 22 , comprising said hot working and/or cold working to the desired work piece form.