Ni-Cr-Co alloy for advanced gas turbine engines

Abstract

A wrought age-hardenable nickel-chromium-cobalt based alloy suitable for use in high temperature gas turbine transition ducts possessing a combination of three specific key properties, namely resistance to strain age cracking, good thermal stability, and good creep-rupture strength contains in weight percent 17 to 22 chromium, 8 to 15 cobalt, 4.0 to 9.5 molybdenum, up to 7 tungsten, 1.28 to 1.65 aluminum, 1.50 to 2.30 titanium, up to 0.80 niobium, 0.01 to 0.2 carbon, up to 0.01 boron, and up to 3 iron, with a balance of nickel and impurities. Certain alloying elements must be present in amounts according to two equations here disclosed.

1 . A nickel-chromium-cobalt based alloy having a composition comprised in weight percent of: 
 17 to 22 chromium    8 to 15 cobalt    4.0 to 9.5 molybdenum    up to 7.0 tungsten    1.28 to 1.65 aluminum    1.50 to 2.30 titanium    up to 0.80 niobium    0.01 to 0.2 carbon    up to 0.015 boron    with a balance of nickel and impurities, the alloy further satisfying the following compositional relationships defined with elemental quantities being in terms of weight percent:      2.2<Al+0.56Ti+0.29Nb<2.9  6.5<Mo+0.52W<9.5    
   
   
       2 . The nickel-chromium-cobalt based alloy of  claim 1 , also containing iron up to 3 weight percent.  
   
   
       3 . The nickel-chromium-cobalt based alloy of  claim 1 , also containing in weight percent at least one of tantalum, up to 1.5%, manganese, up to 1.5%, silicon, up to 0.5%, and copper, up to 0.5%.  
   
   
       4 . The nickel-chromium-cobalt based alloy of  claim 1 , also containing at least one element selected from the group consisting of magnesium, calcium, hafnium, zirconium, yttrium, cerium, and lanthanum, wherein each said element present comprises up to 0.5 weight percent of the alloy.  
   
   
       5 . The nickel-chromium-cobalt based alloy of  claim 1 , wherein the alloy is in wrought form selected from the group consisting of sheets, plates, bars, wires, tubes, pipes, and forgings.  
   
   
       6 . The nickel-chromium-cobalt based alloy of  claim 1 , wherein the alloy is in cast form.  
   
   
       7 . The nickel-chromium-cobalt based alloy of  claim 1 , wherein the alloy has been spray-formed.  
   
   
       8 . The nickel-chromium-cobalt based alloy of  claim 1 , wherein the alloy is in powder metallurgy form.  
   
   
       9 . The nickel-chromium-cobalt based alloy of  claim 1  wherein the alloy is formed as a component for a gas turbine engine.  
   
   
       10 . A nickel-chromium-cobalt based alloy, suitable for use in gas turbine transition ducts, having a composition in weight percent consisting essentially of: 
 17.5 to 21.3 chromium    8.3 to 14.2 cobalt    4.3 to 9.3 molybdenum    up to 7.0 tungsten    1.29 to 1.63 aluminum    1.59 to 2.28 titanium    up to 0.79 niobium    0.034 to 0.097 carbon    0.002 to 0.007 boron    up to 2.6 iron    with a balance of nickel and impurities, the alloy further satisfying the following compositional relationships defined with elemental quantities being in terms of weight percent:      2.35<Al+0.56Ti+0.29Nb<2.84  7.1<Mo+0.52W<9.3    
   
   
       11 . The nickel-chromium-cobalt based alloy of  claim 10 , also containing in weight percent at least one of tantalum, up to 1.5%, manganese, up to 1.5%, silicon, up to 0.5%, and copper, up to 0.5%.  
   
   
       12 . The nickel-chromium-cobalt based alloy of  claim 10 , also containing up to at least one element selected from the group consisting of magnesium, calcium, hafnium, zirconium, yttrium, cerium, and lanthanum, wherein each said element present comprises up to 0.05 weight percent of the alloy.  
   
   
       13 . The nickel-chromium-cobalt based alloy of  claim 10 , wherein the alloy is in wrought forms selected from the group consisting of sheets, plates, bars, wires, tubes, pipes, and forgings.  
   
   
       14 . The nickel-chromium-cobalt based alloy of  claim 10 , wherein the alloy is in cast form.  
   
   
       15 . The nickel-chromium-cobalt based alloy of  claim 10 , wherein the alloy has been spray-formed.  
   
   
       16 . The nickel-chromium-cobalt based alloy of  claim 10 , wherein the alloy is in powder metallurgy form.  
   
   
       17 . The nickel-chromium-cobalt based alloy of  claim 10  wherein the alloy is formed as a component for a gas turbine engine.  
   
   
       18 . An improved gas turbine engine of the type having a plurality of metal components wherein the improvement comprises at least one of the metal components is comprised in weight percent of: 
 17 to 22 chromium    8 to 15 cobalt    4.0 to 9.5 molybdenum    up to 7.0 tungsten    1.28 to 1.65 aluminum    1.50 to 2.30 titanium    up to 0.80 niobium    0.01 to 0.2 carbon    up to 0.015 boron    with a balance of nickel and impurities, the alloy further satisfying the following compositional relationships defined with elemental quantities being in terms of weight percent:      2.2<Al+0.56Ti+0.29Nb<2.9  6.5<Mo+0.52W<9.5    
   
   
       19 . The improved gas turbine engine wherein the at least one of the metal components is a transition duct.  
   
   
       20 . The improved gas turbine engine of  claim 18  where the at least one of the metal components in weight percent consists essentially of: 
 17.5 to 21.3 chromium    8.3 to 14.2 cobalt    4.3 to 9.3 molybdenum    up to 7.0 tungsten    1.29 to 1.63 aluminum    1.59 to 2.28 titanium    up to 0.79 niobium    0.034 to 0.097 carbon    0.002 to 0.007 boron    up to 2.6 iron    with a balance of nickel and impurities, the alloy further satisfying the following compositional relationships defined with elemental quantities being in terms of weight percent:      2.35<Al+0.56Ti+0.29Nb<2.84  7.1<Mo+0.52W<9.3