Nickel-base alloy, articles formed therefrom, and process therefor

Abstract

A composition and process for a nickel-base alloy that exhibits a desirable balance of high-temperature strength and weldability, as well as other properties suitable for high temperature applications. These properties are achieved with an alloy in which the combined level of titanium, aluminum, niobium, and tantalum is carefully controlled. The alloy consists of, by weight, 10 to less than 20% chromium, 15 to 20% cobalt, less than 1.0% molybdenum, 2.5 to 5% tungsten, 1.1 to 1.5% niobium, less than 0.5% tantalum, 3.0 to 3.9% titanium, 2.5 to 3.4% aluminum, 0.07 to 0.15% carbon, less than 0.06% zirconium, less than 0.03% boron, the balance nickel and impurities.

1 . A castable weldable nickel-base alloy consisting of, by weight, 10 to less than 20% chromium, 15 to 20% cobalt, less than 1.0% molybdenum, 2.5 to 5% tungsten, 1.1 to 1.5% niobium, less than 0.5% tantalum, 3.0 to 3.9% titanium, 2.5 to 3.4% aluminum, 0.07 to 0.15% carbon, less than 0.06% zirconium, less than 0.03% boron, the balance nickel and impurities.  
   
   
       2 . The alloy according to  claim 1 , wherein the chromium content in the alloy is, by weight, 14.0 to 15.6%.  
   
   
       3 . The alloy according to  claim 1 , wherein the cobalt content in the alloy is, by weight, 16.0 to 18.0%.  
   
   
       4 . The alloy according to  claim 1 , wherein the tungsten content in the alloy is, by weight, 2.75 to 3.25%.  
   
   
       5 . The alloy according to  claim 1 , wherein the molybdenum content is, by weight, less than 0.5%.  
   
   
       6 . The alloy according to  claim 1 , wherein the niobium content is, by weight, 1.2 to 1.4%.  
   
   
       7 . The alloy according to  claim 1 , wherein the tantalum content is, by weight, less than 0.25%.  
   
   
       8 . The alloy according to  claim 1 , wherein the titanium content is, by weight, 3.1 to 3.4%.  
   
   
       9 . The alloy according to  claim 1 , wherein the aluminum content is, by weight, 2.6 to 3.0%.  
   
   
       10 . The alloy according to  claim 1 , wherein the titanium, aluminum, niobium, and tantalum, contents are, by weight, 3.1 to 3.4%, 2.6 to 3.0%, 1.2 to 1.4%, and less than 0.25%, respectively.  
   
   
       11 . The alloy according to  claim 1 , wherein the carbon, zirconium, and boron contents are, by weight, 0.09 to 0.11%, less than 0.02%, and less than 0.015%, respectively.  
   
   
       12 . The alloy according to  claim 1 , wherein the atomic ratio of titanium to aluminum in the alloy is less than 1.0.  
   
   
       13 . The alloy according to  claim 1 , wherein the alloy is in the form of a casting produced by a process chosen from the group consisting of investment casting, equiax casting, directional solidification, and single-crystal casting.  
   
   
       14 . The alloy according to  claim 1 , wherein the alloy is in the form of a body formed of a compacted powder of the alloy.  
   
   
       15 . The alloy according to  claim 1 , wherein the alloy is in the form of a gas turbine engine component chosen from the group consisting of blade and nozzle components.  
   
   
       16 . A weldable nickel-base alloy casting consisting of, by weight, 14.0 to 15.6% chromium, 16.0 to 18.0% cobalt, less than 0.5% molybdenum, 2.75 to 3.25% tungsten, 1.2 to 1.4% niobium, less than 0.25% tantalum, 3.1 to 3.4% titanium, 2.6 to 3.0% aluminum, 0.09 to 0.11% carbon, less than 0.02% zirconium, less than 0.015% boron, the balance nickel and impurities, wherein the atomic ratio of titanium to aluminum is less than 0.9.  
   
   
       17 . The weldable nickel-base alloy casting according to  claim 16 , wherein the casting has a composition of, by weight, about 14.8% chromium, about 17.2% cobalt, less than 0.25% molybdenum, about 3.0% tungsten, about 1.3% niobium, less than 0.05% tantalum, about 3.2% titanium, about 2.8% aluminum, about 0.10% carbon, about 0.01% zirconium, about 0.01% boron, the balance nickel and impurities.  
   
   
       18 . The weldable nickel-base alloy casting according to  claim 16 , wherein the casting is a nozzle component of a gas turbine engine.  
   
   
       19 . The weldable nickel-base alloy casting according to  claim 16 , wherein the casting is a blade component of a gas turbine engine.  
   
   
       20 . A process for producing a weldable nickel-base alloy casting, the process comprising the steps of: 
 forming a melt consisting of, by weight, 10 to less than 20% chromium, 15 to 20% cobalt, less than 1.0% molybdenum, 2.5 to 5% tungsten, 1.1 to 1.5% niobium, less than 0.5% tantalum, 3.0 to 3.9% titanium, 2.5 to 3.4% aluminum, 0.07 to 0.15% carbon, less than 0.06% zirconium, less than 0.03% boron, the balance nickel and impurities; and    producing a casting from the melt by a process chosen from the group consisting of investment casting, equiax casting, directional solidification, and single-crystal casting.