Fabricable, High Strength, Oxidation Resistant Ni-Cr-Co-Mo-Al Alloys

Abstract

Ni—Cr—Co—Mo—Al based alloys are disclosed which contain 15 to 20 wt. % chromium, 9.5 to 20 wt. % cobalt, 7.25 to 10 wt. % molybdenum, 2.72 to 3.9 wt. % aluminum, along with typical impurities, a tolerance for up to 10.5 wt. % iron, minor element additions and a balance of nickel. These alloys are readily fabricable, have high creep strength, and excellent oxidation resistance up to as high as 2100° F. (1149° C.). This combination of properties is useful for a variety of gas turbine engine components, including, for example, combustors.

We claim: 
     
         1 . A nickel-chromium-cobalt-molybdenum-aluminum based alloy having a composition comprised in weight percent of: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     15 to 20 
                   chromium 
                 
                     
                    9.5 to 20 
                   cobalt 
                 
                     
                   7.25 to 10 
                   molybdenum 
                 
                     
                   2.72 to 3.9 
                   aluminum 
                 
                     
                   up to 10.5 
                   iron 
                 
                     
                   present up to 0.15 
                   carbon 
                 
                     
                   up to 0.015 
                   boron 
                 
                     
                   up to 0.75 
                   titanium 
                 
                     
                   up to 1.5 
                   tantalum 
                 
                     
                   up to 1 
                   hafnium 
                 
                     
                   up to 1 
                   manganese 
                 
                     
                   up to 0.6 
                   silicon 
                 
                     
                   up to 0.06 
                   zirconium 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
         with a balance of nickel and impurities, the alloy further satisfying the following compositional relationship defined with elemental quantities being in terms of weight percent:
   Al+0.56Ti+0.29Nb+0.15Ta≦3.9.
 
 
       
     
     
         2 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 1 , containing hafnium, tantalum, or a combination of hafnium and tantalum, where the sum of the two elements is between 0.2 wt. % and 1.5 wt. %. 
     
     
         3 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 1 , containing titanium, from 0.2 to 0.75 wt. %. 
     
     
         4 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 1 , containing at least one of the elements hafnium and tantalum at a level ranging from 0.2 wt. % up to 1 and 1.5 wt. %, respectively. 
     
     
         5 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 1 , containing traces of at least one of magnesium, calcium, and any rare earth elements up to 0.05 wt. %. 
     
     
         6 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 1 , containing at least one of the following impurities: copper up to 0.5 wt. %, sulfur up to 0.015 wt. %, and phosphorous up to 0.03 wt. %. 
     
     
         7 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 1  wherein the alloy contains in weight percent: 
       
         
           
                 
                 
               
                     
                 
                   16 to 20 
                   chromium 
                 
                   15 to 20 
                   cobalt 
                 
                   7.25 to 9.75 
                   molybdenum 
                 
                   2.9 to 3.7 
                   aluminum 
                 
                     
                 
             
                
               
               
                
                
                
                
                
               
            
           
         
       
     
     
         8 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 1 , wherein the alloy contains in weight percent: 
       
         
           
                 
                 
               
                     
                 
                   17 to 20 
                   chromium 
                 
                   17 to 20 
                   cobalt 
                 
                   7.25 to 9.25 
                   molybdenum 
                 
                   2.9 to 3.6 
                   aluminum 
                 
                     
                 
             
                
               
               
                
                
                
                
                
               
            
           
         
       
     
     
         9 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 1 , wherein the alloy contains in weight percent: 
       
         
           
                 
                 
               
                     
                 
                   17.5 to 19.5 
                   chromium 
                 
                   17.5 to 19.5 
                   cobalt 
                 
                   7.25 to 8.25 
                   molybdenum 
                 
                   3.0 to 3.5 
                   aluminum 
                 
                     
                 
             
                
               
               
                
                
                
                
                
               
            
           
         
       
     
     
         10 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 1 , wherein the alloy contains in weight percent: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   up to 5 
                   iron 
                 
                     
                   present up to 0.12 
                   carbon 
                 
                     
                   up to 0.008 
                   boron 
                 
                     
                   up to 0.5 
                   silicon 
                 
                     
                   up to 0.04 
                   zirconium 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
                
               
            
           
         
       
     
     
         11 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 1 , wherein the alloy contains in weight percent: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   up to 2 
                   iron 
                 
                     
                   0.02 to 0.12 
                   carbon 
                 
                     
                   present up to 0.005 
                   boron 
                 
                     
                    0.2 to 0.5 
                   titanium 
                 
                     
                   up to 0.5 
                   manganese 
                 
                     
                   up to 0.4 
                   silicon 
                 
                     
                   present up to 0.04 
                   zirconium 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         12 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 1 , wherein the alloy has oxidation resistance such that the average metal affected has a value not greater than 2.5 mils/side when tested in flowing air at 2100° F. (1149° C.) for 1008 hours. 
     
     
         13 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 1 , wherein the alloy has modified CHRT test ductility values greater than 7%. 
     
     
         14 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 1 , wherein the alloy has a creep-rupture life of at least 325 hours when tested at 1800° F. (982° C.) under a load of 2.5 ksi (17 MPa). 
     
     
         15 . A nickel-chromium-cobalt-molybdenum-aluminum based alloy having a composition comprised in weight percent of: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     15 to 20 
                   chromium 
                 
                     
                    9.5 to 20 
                   cobalt 
                 
                     
                   7.25 to 10 
                   molybdenum 
                 
                     
                   2.72 to 3.9 
                   aluminum 
                 
                     
                   up to 5 
                   iron 
                 
                     
                   present up to 0.15 
                   carbon 
                 
                     
                   up to 0.015 
                   boron 
                 
                     
                   up to 0.75 
                   titanium 
                 
                     
                   up to 1 
                   niobium 
                 
                     
                   up to 1.5 
                   tantalum 
                 
                     
                   up to 1 
                   hafnium 
                 
                     
                   up to 2 
                   tungsten 
                 
                     
                   up to 1 
                   manganese 
                 
                     
                   up to 0.6 
                   silicon 
                 
                     
                   up to 0.06 
                   zirconium 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
         with a balance of nickel and impurities, the alloy further satisfying the following compositional relationship defined with elemental quantities being in terms of weight percent:
   Al+0.56Ti+0.29Nb+0.15Ta≦3.9.
 
 
       
     
     
         16 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 15 , containing hafnium, tantalum, or a combination of hafnium and tantalum, where the sum of the two elements is between 0.2 wt. % and 1.5 wt. %. 
     
     
         17 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 15 , containing at least one of hafnium, tantalum, and niobium, where the sum of these elements is between 0.2 wt. % and 1.5 wt. %. 
     
     
         18 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 15 , containing titanium, from 0.2 to 0.75 wt. %. 
     
     
         19 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 15 , containing at least one of the elements niobium, hafnium, and tantalum at a level ranging from 0.2 wt. % up to 1, 1, and 1.5 wt. %, respectively. 
     
     
         20 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 15 , containing traces of at least one of magnesium, calcium, and any rare earth elements up to 0.05 wt. %. 
     
     
         21 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 15 , containing at least one of: copper up to 0.5 wt. %, sulfur up to 0.015 wt. %, and phosphorous up to 0.03 wt. %. 
     
     
         22 . A nickel-chromium-cobalt-molybdenum-aluminum based alloy having a composition comprised in weight percent of: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                    15.3 to 19.9 
                   chromium 
                 
                     
                    9.7 to 20.0 
                   cobalt 
                 
                     
                    7.5 to 10.0 
                   molybdenum 
                 
                     
                    2.72 to 3.78 
                   aluminum 
                 
                     
                    0.1 to 10.4 
                   iron 
                 
                     
                   0.085 to 0.120 
                   carbon 
                 
                     
                   up to 0.005 
                   boron 
                 
                     
                   up to 0.49 
                   titanium 
                 
                     
                   up to 1.0 
                   tantalum 
                 
                     
                   up to 0.48 
                   hafnium 
                 
                     
                   up to 0.49 
                   silicon 
                 
                     
                   up to 0.02 
                   yttrium 
                 
                     
                   up to 0.04 
                   zirconium 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
         with a balance of nickel and impurities, the alloy further satisfying the following compositional relationship defined with elemental quantities being in terms of weight percent:
   Al+0.56Ti+0.29Nb+0.15Ta≦3.89.
 
 
       
     
     
         23 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 22 , containing up to 4.5 wt. % iron and at least one of tungsten or niobium at a level of up to 1.94 wt. % tungsten and up to 0.91 wt. % niobium. 
     
     
         24 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 22 , containing traces of at least one of magnesium, calcium, and any rare earth elements up to 0.05 wt. %. 
     
     
         25 . The nickel-chromium-cobalt-molybdenum-aluminum based alloy of  claim 22 , containing one or more of the following impurities: niobium up to 0.2 wt. %, tungsten up to 0.5 wt. %, copper up to 0.5 wt. %, sulfur up to 0.015 wt. %, and phosphorous up to 0.03 wt. %.