Nickel-base alloy

Abstract

The invention is a class of nickel-base alloys for gas turbine applications, comprising, by weight, about 13.7 to about 14.3 percent chromium, about 5.0 to about 10.0 percent cobalt, about 3.5 to about 5.2 percent tungsten, about 2.8 to about 5.2 percent titanium, about 2.8 to about 4.6 percent aluminum, about 0.0 to about 3.5 percent tantalum, about 1.0 to about 1.7 percent molybdenum, about 0.08 to about 0.13 percent carbon, about 0.005 to about 0.02 percent boron, about 0.0 to about 1.5 percent niobium, about 0.0 to about 2.5 percent hafnium, about 0.0 to about 0.04 percent zirconium, and the balance substantially nickel. The nickel-base alloys may be provided in the form of useful articles of manufacture, and which possess a unique combination of mechanical properties, microstructural stability, resistance to localized pitting and hot corrosion in high temperature corrosive environments, and high yields during the initial forming process as well as post-forming manufacturing and repair processes.

1 . An alloy comprising the following elements, by weight:
 a. about 13.7 to about 14.3 percent chromium,   b. about 5.0 to about 10.0 percent cobalt,   c. about 3.5 to about 5.2 percent tungsten,   d. about 2.8 to about 5.2 percent titanium,   e. about 2.8 to about 4.6 percent aluminum,   f. about 0.0 to about 3.5 percent tantalum,   g. about 1.0 to about 1.7 percent molybdenum,   h. about 0.08 to about 0.13 percent carbon,   i. about 0.005 to about 0.02 percent boron,   j. about 0.0 to about 1.5 percent niobium,   k. about 0.0 to about 2.5 percent hafnium,   l. about 0.0 to about 0.04 percent zirconium,   m. the balance substantially nickel.   
     
     
         2 . The alloy of  claim 1 , comprising about 4.0 to about 4.6 percent tungsten. 
     
     
         3 . The alloy of  claim 1 , comprising about 3.6 to about 4.3 percent titanium. 
     
     
         4 . The alloy of  claim 1 , comprising about 3.5 to about 3.9 percent aluminum. 
     
     
         5 . The alloy of  claim 1 , comprising about 3.1 to about 3.5 percent tantalum. 
     
     
         6 . The alloy of  claim 1 , comprising about 0.0 to about 1.5 percent niobium or about 0.0 to about 3.5 percent tantalum. 
     
     
         7 . The alloy of  claim 1 , wherein the ratio of percent aluminum to percent titanium is about 0.8 to about 1.0, by weight. 
     
     
         8 . An alloy comprising the following elements, by weight, and having about zero Eta phase (Ni 3 Ti) and segregated titanium:
 a. about 13.7 to about 14.3 percent chromium,   b. about 5.0 to about 10.0 percent cobalt,   c. about 3.5 to about 5.2 percent tungsten,   d. about 2.8 to about 5.2 percent titanium,   e. about 2.8 to about 4.6 percent aluminum,   f. about 0.0 to about 3.5 percent tantalum,   g. about 1.0 to about 1.7 percent molybdenum,   h. about 0.08 to about 0.13 percent carbon,   i. about 0.005 to about 0.02 percent boron,   j. about 0.0 to about 1.5 percent niobium,   k. about 0.0 to about 2.5 percent hafnium,   l. about 0.0 to about 0.04 percent zirconium,   m. the balance substantially nickel.   
     
     
         9 . The alloy of  claim 8 , comprising about 4.0 to about 4.6 percent tungsten. 
     
     
         10 . The alloy of  claim 8 , comprising about 3.6 to about 4.3 percent titanium. 
     
     
         11 . The alloy of  claim 8 , comprising about 3.5 to about 3.9 percent aluminum. 
     
     
         12 . The alloy of  claim 8 , comprising about 3.1 to about 3.5 percent tantalum. 
     
     
         13 . The alloy of  claim 8 , comprising about 0.0 to about 1.5 percent niobium or about 0.0 to about 3.5 percent tantalum. 
     
     
         14 . The alloy of  claim 8 , wherein the ratio of percent aluminum to percent titanium is about 0.8 to about 1.0, by weight. 
     
     
         15 . An alloy comprising the following elements, by weight:
 a. about 13.9 percent chromium,   b. about 9.5 percent cobalt,   c. about 4.5 percent tungsten,   d. about 4.2 percent titanium,   e. about 3.7 percent aluminum,   f. about 3.4 percent tantalum,   g. about 1.6 percent molybdenum,   h. about 0.1 percent carbon,   i. about 0.01 percent boron,   j. less than 0.01 percent zirconium,   k. the balance substantially nickel.   
     
     
         16 . An alloy comprising the following elements, by weight:
 a. about 13.9 percent chromium,   b. about 9.5 percent cobalt,   c. about 4.2 percent tungsten,   d. about 3.7 percent titanium,   e. about 3.7 percent aluminum,   f. about 3.2 percent tantalum,   g. about 1.5 percent molybdenum,   h. about 0.1 percent carbon,   i. about 0.01 percent boron,   j. about 0.002 percent zirconium,   k. the balance substantially nickel.   
     
     
         17 . An article of manufacture that may be used in a gas turbine and is formed from an alloy comprising the following elements, by weight:
 a. about 13.7 to about 14.3 percent chromium,   b. about 5.0 to about 10.0 percent cobalt,   c. about 3.5 to about 5.2 percent tungsten,   d. about 2.8 to about 5.2 percent titanium,   e. about 2.8 to about 4.6 percent aluminum,   f. about 0.0 to about 3.5 percent tantalum,   g. about 1.0 to about 1.7 percent molybdenum,   h. about 0.08 to about 0.13 percent carbon,   i. about 0.005 to about 0.02 percent boron,   j. about 0.0 to about 1.5 percent niobium,   k. about 0.0 to about 2.5 percent hafnium,   l. about 0.0 to about 0.04 percent zirconium,   m. the balance substantially nickel.   
     
     
         18 . The alloy of  claim 17 , comprising about 4.0 to about 4.6 percent tungsten. 
     
     
         19 . The alloy of  claim 17 , comprising about 3.6 to about 4.3 percent titanium. 
     
     
         20 . The alloy of  claim 17 , comprising about 3.5 to about 3.9 percent aluminum. 
     
     
         21 . The alloy of  claim 17 , comprising about 3.1 to about 3.5 percent tantalum. 
     
     
         22 . The alloy of  claim 17 , comprising about 0.0 to about 1.5 percent niobium or about 0.0 to about 3.5 percent tantalum. 
     
     
         23 . The alloy of  claim 17 , wherein the ratio of percent aluminum to percent titanium is about 0.8 to about 1.0, by weight. 
     
     
         24 . The article of  claim 17 , wherein the method of forming is casting. 
     
     
         25 . The article of  claim 24 , wherein the method of forming is casting performed in such a manner as to produce an equiaxed grain structure. 
     
     
         26 . The article of  claim 24 , wherein the method of forming is casting performed in such a manner as to produce a directionally solidified grain structure. 
     
     
         27 . The article of  claim 24 , wherein the method of forming is casting performed in such a manner as to produce a single crystal grain structure. 
     
     
         28 . The article of  claim 17 , wherein that article is a gas turbine bucket or other form of rotating airfoil located in the turbine hot section. 
     
     
         29 . The article of  claim 17 , wherein that article is a gas turbine nozzle or other form of stationary airfoil located in the turbine hot section. 
     
     
         30 . An article that may be used in a gas turbine and is formed from an alloy comprising the following elements, by weight:
 a. about 13.9 percent chromium,   b. about 9.5 percent cobalt,   c. about 4.5 percent tungsten,   d. about 4.2 percent titanium,   e. about 3.7 percent aluminum,   f. about 3.4 percent tantalum,   g. about 1.6 percent molybdenum,   h. about 0.1 percent carbon,   i. about 0.01 percent boron,   j. less than 0.01 percent zirconium,   k. the balance substantially nickel.   
     
     
         31 . The article of  claim 30 , wherein the method of forming is casting. 
     
     
         32 . The article of  claim 31 , wherein the method of forming is casting performed in such a manner as to produce an equiaxed grain structure. 
     
     
         33 . The article of  claim 30 , wherein that article is a gas turbine bucket or other form of rotating airfoil located in the turbine hot section. 
     
     
         34 . The article of  claim 30 , wherein that article is a gas turbine nozzle or other form of stationary airfoil located in the turbine hot section. 
     
     
         35 . An article that may be used in a gas turbine and is formed from an alloy comprising the following elements, by weight:
 a. about 13.9 percent chromium,   b. about 9.5 percent cobalt,   c. about 4.2 percent tungsten,   d. about 3.7 percent titanium,   e. about 3.7 percent aluminum,   f. about 3.2 percent tantalum,   g. about 1.5 percent molybdenum,   h. about 0.1 percent carbon,   i. about 0.01 percent boron,   j. about 0.002 percent zirconium,   k. the balance substantially nickel.   
     
     
         36 . The article of  claim 35 , wherein the method of forming is casting. 
     
     
         37 . The article of  claim 36 , wherein the method of forming is casting performed in such a manner as to produce a directionally solidified grain structure. 
     
     
         38 . The article of  claim 35 , wherein that article is a gas turbine bucket or other form of rotating airfoil located in the turbine hot section. 
     
     
         39 . The article of  claim 35 , wherein that article is a gas turbine nozzle or other form of stationary airfoil located in the turbine hot section.