Precipitation hardening nickel-base alloy, part made of said alloy, and manufacturing method thereof

Abstract

A precipitation hardened nickel-base alloy, characterized in that its composition is, in weight percentages: 18%≦Cr≦22%, preferably 18%≦Cr≦20%; 18%≦Co≦22%, preferably 19%≦Co≦21%; 4%≦Mo+W≦8%, preferably 5.5%≦Mo+W≦7.5%; trace amounts≦Zr≦0.06%; trace amounts≦B≦0.03%. preferably trace amounts≦B≦0.01%; trace amounts≦C≦0.1%, preferably trace amounts≦C≦0.06%; trace amounts≦Fe≦1%; trace amounts≦Nb≦0.01%; trace amounts≦Ta≦0.01%; trace amounts≦S≦0.008%; trace amounts≦P≦0.015%; trace amounts≦Mn≦0.3%; trace amounts≦Si≦0.15%; trace amounts≦O≦0.0025%; trace amounts≦N≦0.0030%; the remainder being nickel and impurities resulting from the elaboration, the Al and Ti contents further satisfying the conditions: Ti/Al≦3;  (1) Al+1.2 Ti≧2%;  (2) (0.2 Al−1.25) 2 −0.5 Ti≧0%;  (3) Ti+1.5 Al≦4.5%.  (4) Part made in this alloy and its manufacturing method.

1 . A precipitation hardened nickel-base alloy, wherein its composition consists of, in weight percentages:
 18%≦Cr≦22%;   18%≦Co≦22%;   4%≦Mo+W≦8%;   trace amounts≦Zr≦0.06%;   trace amounts≦B≦0.03%;   trace amounts≦C≦0.1%, preferably trace amounts≦C≦0.06%;   trace amounts≦Fe≦1%;   trace amounts≦Nb≦0.01%;   trace amounts≦Ta≦0.01%;   trace amounts≦S≦0.008%;   trace amounts≦P≦0.015%;   trace amounts≦Mn≦0.3%;   trace amounts≦Si≦0.15%;   trace amounts≦O≦0.0025%;   trace amounts≦N≦0.0030%;   
       the remainder being nickel and impurities resulting from the elaboration, the Al and Ti contents further satisfying the conditions:
   Ti/Al≦3;  (1)
 
   Al+1.2 Ti≧2%;  (2)
 
   (0.2 Al−1.25) 2 −0.5 Ti≧0%; and  (3)
 
   Ti+1.5 Al≦4.5%.  (4)
 
 
     
     
         2 . The alloy according to  claim 1 , characterized in that its γ′ phase fraction is comprised between 5 and 20%. 
     
     
         3 . The alloy according to  claim 1 , characterized in that the solvus temperature of its γ′ phase is less than or equal to 980° C. 
     
     
         4 . A method for manufacturing a part in a nickel-base alloy, wherein an ingot is prepared, having the composition according to  claim 1 , it is homogenized at a temperature of at least 1,150° C. for 24 to 72 h, it is hot-worked by forging or rolling in a supersolvus temperature range, it is put into solution at a temperature from 1,100 to 1,200° C. for 1 to 4 h, it is cooled at a rate of at least 1° C./min, for example in water, it is aged at a temperature from 750 to 850° C. for 7 to 10 h, and it is cooled for example in calm air or in an enclosure. 
     
     
         5 . A nickel-base alloy part, which was prepared according to the method of  claim 4 . 
     
     
         6 . The part according to  claim 5 , wherein it is an element of a land or aeronautical turbine engine. 
     
     
         7 . The alloy according to  claim 1 , wherein 18%≦Cr≦20%. 
     
     
         8 . The alloy according to  claim 1 , wherein 19%≦Co≦21%. 
     
     
         9 . The alloy according to  claim 1 , wherein 5.5%≦Mo+W≦7.5%. 
     
     
         10 . The alloy according to  claim 1 , wherein trace amounts≦B≦0.01%. 
     
     
         11 . The alloy according to  claim 1 , wherein trace amounts≦C≦0.06%. 
     
     
         12 . The part according to  claim 5 , wherein it is an element of an aeronautical turbine engine.