Cu-ni-mn-al alloys

Abstract

Strength and hardness of a copper-nickel-aluminium-manganese alloy is improved where the alloy contains nickel in the range ≧21% to ≦26% by weight, aluminium in the range ≧2.1% to ≦3.2% by weight and the Ni:Al ratio is between 8 and 10 (in terms of wt %).

1 . A Cu—Ni—Mn—Al alloy containing nickel in the range ≧21% to ≦26% by weight, aluminium in the range ≧2.1% to ≦3.2% by weight and which possesses a Ni:Al ratio of between 8 and 10 (in terms of wt %).  
   
   
       2 . The alloy of  claim 1  further including iron, chromium and niobium.  
   
   
       3 . The alloy of  claim 2  further including one or more of titanium, vanadium, silicon, tantalum or tungsten.  
   
   
       4 . A Cu—Ni—Mn—Al alloy having Ni:Al ratio of between 8 and 10 (in terms of wt %) and the composition (% by weight):  
     
       
         
               
               
               
             
                   
                   
               
                   
                   
               
                   
                 Nickel 
                 21.0-26.0 
               
                   
                 Aluminium 
                 2.1-3.2 
               
                   
                 Manganese 
                 2.8-4.1 
               
                   
                 Iron 
                 0.4-1.5 
               
                   
                 Chromium 
                 0.3-1.5 
               
                   
                 Niobium 
                 0.7-1.2 
               
                   
                 Titanium 
                 0.0-0.5 
               
                   
                 Tungsten 
                 0.0-0.5 
               
                   
                 Tantalum 
                 0.0-0.5 
               
                   
                 Silicon 
                 0.0-0.5 
               
                   
                 Vanadium 
                 0.0-0.5 
               
                   
                 Copper 
                 Remainder 
               
                   
                   
               
                   
                   
               
           
              
              
             
             
              
              
              
              
              
              
              
              
              
              
              
              
              
              
             
          
         
       
     
   
   
       5 . The alloy according to  claim 4  wherein the nickel, aluminium, and manganese are present in the following amounts (% by weight):  
     
       
         
               
               
               
             
                   
                   
               
                   
                   
               
                   
                 Nickel 
                 21.5-24.0 
               
                   
                 Aluminium 
                 2.2-2.5 
               
                   
                 Manganese 
                 3.0-4.1 
               
                   
                 Iron 
                 0.4-1.1 
               
                   
                 Chromium 
                 0.3-1.4 
               
                   
                 Niobium 
                 0.7-1.2 
               
                   
                   
               
                   
                   
               
           
              
              
             
             
              
              
              
              
              
              
              
              
             
          
         
       
     
   
   
       6 . The alloy according to  claim 5  wherein the nickel, aluminium, and manganese are present in the following amounts (% by weight):  
     
       
         
               
               
               
             
                   
                   
               
                   
                   
               
                   
                 Nickel 
                 21.9-22.1 
               
                   
                 Aluminium 
                 2.4-2.5 
               
                   
                 Manganese 
                 3.0-3.1 
               
                   
                   
               
                   
                   
               
           
              
              
             
             
              
              
              
              
              
             
          
         
       
     
   
   
       7 . The alloy according to  claim 1  having the following properties after thermo-mechanical processing in the temperature range 800° C. to 1000° C. and heat treatment in the temperature range 350° C. to 600° C.:  
     
       
         
               
               
               
             
                   
                   
               
                   
                   
               
                   
                 0.2% Proof Stress 
                  ≧850 N/mm 2   
               
                   
                 Tensile Strength 
                 ≧1000 N/mm 2   
               
                   
                 Elongation (5.65 √S 0 ) 
                   ≧8% 
               
                   
                 Hardness 
                  ≧280 BHN 
               
                   
                   
               
                   
                   
               
           
              
              
             
             
              
              
              
              
              
              
             
          
         
       
     
   
   
       8 . The alloy according to  claim 7  wherein the 0.2% proof stress is ≧900 N/mm 2 .  
   
   
       9 . The alloy according to  claim 7  wherein the hardness is ≧300 BHN.  
   
   
       10 . The alloy according to  claim 1  wherein the Ni:Al ratio is ≧9.  
   
   
       11 . (canceled)  
   
   
       12 . (canceled)  
   
   
       13 . The alloy according to  claim 4  having the following properties after thermo-mechanical processing in the temperature range 800° C. to 1000° C. and heat treatment in the temperature range 350° C. to 600° C.:  
     
       
         
               
               
               
             
                   
                   
               
                   
                   
               
                   
                 0.2% Proof Stress 
                  ≧850 N/mm 2   
               
                   
                 Tensile Strength 
                 ≧1000 N/mm 2   
               
                   
                 Elongation (5.65 √S 0 ) 
                   ≧8% 
               
                   
                 Hardness 
                  ≧280 BHN 
               
                   
                   
               
                   
                   
               
           
              
              
             
             
              
              
              
              
              
              
             
          
         
       
     
   
   
       14 . The alloy according to  claim 13  wherein the 0.2% proof stress is ≧900 N/mm 2 .  
   
   
       15 . The alloy according to  claim 13  wherein the hardness is ≧300 BHN.  
   
   
       16 . The alloy according to  claim 4  wherein the Ni:Al ratio is ≧9.