Nickel-based superalloy and parts made from said superalloy

Abstract

A nickel superalloy has the following composition, the concentrations of the different elements being expressed as wt-%: Formula (I), the remainder consisting of nickel and impurities resulting from the production of the superalloy. In addition, the composition satisfies the following equation, wherein the concentrations of the different elements are expressed as atomic percent: Formula (II).

1 . A nickel-based superalloy of the following composition, the contents of the various elements being expressed as weight percentages:
 1.3%≦Al≦2.8%;   trace amounts≦Co≦11%;   14%≦Cr≦17%;   trace amounts≦Fe≦12%;   2%≦Mo≦5%;   0.5%≦Nb+Ta≦2.5%;   2.5%≦Ti≦4.5%;   1%≦W≦4%;   0.0030%≦B≦0.030%;   trace amounts≦C≦0.1%;   0.01%≦Zr≦0.06%;   the remainder consisting of nickel and impurities resulting from the production,   and such that the composition satisfies the following equations wherein the contents are expressed as atomic percentages:
   8≦Al at %+Ti at %+Nb at %+Ta at %≦11
 
   0.7≦(Ti at %+Nb at %+Ta at %)/Al at %≦1.3
 
   
     
     
         2 . The superalloy according to  claim 1 , characterized in that its composition satisfies the following equation wherein the contents are expressed as atomic percentages:
   1≦(Ti at %+Nb at %+Ta at %)/Al at %≦1.3
   
     
     
         3 . The superalloy according to  claim 1 ,  characterized in that it contains between 3 and 12% of Fe, as weight percentages. 
     
     
         4 . The superalloy according to  claim 1 , characterized in that its composition is, expressed as weight percentages:
 1.3%≦Al≦2.8%;   7%≦Co≦11%;   14%≦Cr≦17%;   3%≦Fe≦9%;   2%≦Mo≦5%;   0.5%≦Nb+Ta≦2.5%;   2.5%≦Ti≦4.5%;   1%≦W≦4%;   0.0030%≦B≦0.030%;   trace amounts≦C≦0.1%;   0.01%≦Zr≦0.06%;   and its composition satisfies the following equations wherein the contents are expressed as atomic percentages:
   8≦Al at %+Ti at %+Nb at %+Ta at %≦11
 
   0.7≦(Ti at %+Nb at %+Ta at %)/Al at %≦1.3
 
   theinder consisting of nickel and of impurities resulting from the production.   
     
     
         5 . The superalloy according to  claim 4 , characterized in that 1≦(Ti at %+Nb at %+Ta at %)/Al at %≦1.3. 
     
     
         6 . The superalloy according to  claim 4 , characterized in that its composition is, expressed as weight percentages:
 1.8%≦Al≦2.8%;   7%≦Co≦10%;   14%≦Cr≦17%;   3.6%≦Fe≦7%;   2%≦Mo≦4%;   0.5%≦Nb+Ta≦2%;   2.8%≦Ti≦4.2%;   1.5%≦W≦3.5%;   0.0030%≦B≦0.030%;   trace amounts≦C≦0.07%;   0.01%≦Zr≦0.06%;   and its composition satisfies the following equations wherein the contents are expressed as atomic percentages:
   8≦Al at %+Ti at %+Nb at %+Ta at %≦11
 
   0.7≦(Ti at %+Nb at %+Ta at %)/Al at %≦1.3
 
   the remainder consisting of nickel and of impurities resulting from the production.   
     
     
         7 . The superalloy according to  claim 6 , characterized in that 0.7≦(Ti at %+Nb at %+Ta at %)/Al at %≦1.15. 
     
     
         8 . The superalloy according to  claim 6 , characterized in that 1≦(Ti at %+Nb at %+Ta at %)/Al at %≦1.3. 
     
     
         9 . The superalloy according to  claim 1 , characterized in that it comprises a gamma′ phase fraction comprised between 30 and 44%, preferably between 32 and 42%, and in that the solvus of the gamma′ phase of the superalloy is less than 1,145° C. 
     
     
         10 . The superalloy according to  claim 1 , characterized in that the composition of the alloy satisfies the following equation, wherein the contents of the elements are calculated in the gamma matrix at 700° C. and are expressed as an atomic percent:
   0.717 Ni at %+0.858 Fe at %+1.142 Cr at %+0.777 Co at %+1.55 Mo at %+1.655 W at %+1.9 Al at %+2.271 Ti at %+2.117 Nb at %+2.224 Ta at %≦0.901.
 
 
     
     
         11 . The superalloy according to  claim 1 , characterized in that the Cr content (expressed as an atomic percentage) is, in the gamma matrix at 700° C., greater than 24 at %. 
     
     
         12 . The superalloy according to  claim 1 , characterized in that the Mo+W content (expressed as an atomic percentage) is ≦2.8 at % in the gamma matrix. 
     
     
         13 . A part in a nickel superalloy, characterized in that its composition is according to  claim 1 . 
     
     
         14 . The part in a nickel superalloy according to  claim 12 , characterized in that this is a component of an aeronautical or land gas turbine. 
     
     
         15 . The superalloy according to  claim 2 , characterized in that it contains between 3 and 12% of Fe, as weight percentages.