Rhenium-free nickel base superalloy of low density

Abstract

The invention relates to a substantially rhenium-free nickel base alloy showing a high creep resistance and relatively low density which comprises in % by weight: aluminum from 3.0 to 7.7, cobalt from 0 to 16.8, chromium from 3 to 11.8, molybendum from 3.1 to 11.3, tantalum from 0 to 3.9. In addition to nickel and unavoidable impurities this alloy may further comprise one or more of titanium, tungsten, carbon, phosphorus, copper, zirconium, silicon, hafnium, yttrium, niobium, and germanium.

What is claimed is: 
     
         1 . A nickel base alloy exhibiting high creep resistance and being substantially free of rhenium, wherein the alloy comprises the following elements in % by weight relative to the total weight of the alloy:
 aluminum from 3.0 to 7.7   cobalt from 0 to 16.8   chromium from 3 to 11.8   molybendum from 3.1 to 11.3   tantalum from 0 to 3.9.   
     
     
         2 . The alloy of  claim 1 , wherein the alloy comprises:
 aluminum from 3.4 to 7.7   cobalt from 0 to 16.8   chromium from 4 to 11.8   molybendum from 3.3 to 11.3   tantalum from 0 to 3.9.   
     
     
         3 . The alloy of  claim 1 , wherein the alloy comprises:
 aluminum from 3.8 to 7.7   cobalt from 0 to 16.8   chromium from 5 to 11.8   molybendum from 3.4 to 11.3   tantalum from 0 to 3.9.   
     
     
         4 . The alloy of  claim 1 , wherein the alloy comprises:
 aluminum from 4.1 to 7.7   cobalt from 0 to 16.8   chromium from 6 to 11.8   molybendum from 3.6 to 11.3   tantalum from 0 to 3.9.   
     
     
         5 . The alloy of  claim 1 , wherein the alloy comprises:
 aluminum from 4.7 to 7.7   cobalt from 2.6 to 13.6   chromium from 6.3 to 7.3   molybendum from 3.7 to 4.7   tantalum from 0 to 0.5   titanium from 2.8 to 3.6   tungsten from 7.4 to 8.4.   
     
     
         6 . The alloy of  claim 1 , wherein the alloy comprises:
 aluminum from 5.0 to 5.4   cobalt from 2.9 to 13.3   chromium from 6.6 to 7   molybendum from 4 to 4.4   tantalum from 0 to 0.2   titanium from 3.1 to 3.5   tungsten from 7.7 to 8.1.   
     
     
         7 . The alloy of  claim 1 , wherein the alloy further comprises:
 titanium from 0 to 6.0   tungsten from 0 to 11.3   carbon from 0 to 0.05   phosphorus from 0 to 0.015   copper from 0 to 0.05   zirconium from 0 to 0.015   silicon from 0 to 6.0   sulfur from 0 to 0.001   iron from 0 to 0.15   manganese from 0 to 0.05   boron from 0 to 6.0   hafnium from 0 to 4.0   yttrium from 0 to 0.002   niobium from 0 to 8.0   germanium from 0 to 8.0,   remainder nickel and unavoidable impurities.   
     
     
         8 . The alloy of  claim 7 , wherein the alloy comprises:
 titanium from 0 to 5   silicon from 0 to 5.0   boron from 0 to 5.0   hafnium from 0 to 3.0   niobium from 0 to 6.0   germanium from 0 to 6.0.   
     
     
         9 . The alloy of  claim 8 , wherein the alloy comprises:
 titanium from 0 to 4   silicon from 0 to 4.0   boron from 0 to 4.0   hafnium from 0 to 3.0   niobium from 0 to 4.0   germanium from 0 to 4.0.   
     
     
         10 . The alloy of  claim 9 , wherein the alloy comprises:
 titanium from 0 to 4   silicon from 0 to 4.0   boron from 0 to 4.0   hafnium from 0 to 3.0   niobium from 0 to 4.0   germanium from 0 to 4.0.   
     
     
         11 . The alloy of  claim 10 , wherein the alloy comprises:
 titanium from 0 to 3.6   silicon from 0 to 2.0   boron from 0 to 2.0   hafnium from 0 to 1.0   niobium from 0 to 1.0.   germanium from 0 to 1.0.   
     
     
         12 . The alloy of  claim 1 , wherein the alloy comprises less than 5% by weight cobalt. 
     
     
         13 . The alloy of  claim 1 , wherein the alloy comprises more than 11% by weight cobalt. 
     
     
         14 . The alloy of  claim 1 , wherein the alloy has a density of not higher than 8.5 g/cm 3 . 
     
     
         15 . The alloy of  claim 1 , wherein the alloy has a solidus temperature of higher than 1320° C. 
     
     
         16 . The alloy of  claim 1 , wherein the alloy has a residual eutecticum of not more than 4%. 
     
     
         17 . An article made of the alloy of  claim 1 . 
     
     
         18 . The article of  claim 17 , wherein the article is monocrystalline or directionally solidified. 
     
     
         19 . The article of claim  21 , wherein the article is a component of a gas turbine or an aircraft engine. 
     
     
         20 . A method of making a nickel base alloy, wherein the method comprises melting together metals in proportions which result in the alloy of  claim 1 .