Turbine blade for a gas turbine engine

Abstract

A turbine blade is manufactured as a single-crystal casting from a metal alloy, without a solution heat treatment step.

1 - 6 . (canceled)  
   
   
       7 . A gas turbine engine, characterised in that the engine includes a turbine blade comprising a single-crystal casting of metal alloy having a solvus temperature which is less than its incipient melting point, characterised in that the turbine blade has not been subjected to solution heat treatment after casting.  
   
   
       8 . A gas turbine engine as claimed in  claim 7  wherein the metal alloy is a Ni ALX alloy in which X is one or more of hafnium, rhenium, titanium, chromium or gallium.  
   
   
       9 . A gas turbine engine as claimed in  claim 7  wherein the turbine blade is provided with cavities which are separated from adjacent cavities by internal walls and which are separated from the exterior of the turbine blade by external walls.  
   
   
       10 . A gas turbine engine as claimed in  claim 9  wherein the thickness ratio Ti/Te of the internal and external walls is not greater than 1.5:1.  
   
   
       11 . A gas turbine engine as claimed in  claim 9  wherein at least one of the internal walls is provided with through holes, at least some of which are spaced apart by a spacing(s) which is not greater than 6 times the transverse dimension of the holes.  
   
   
       12 . A gas turbine engine as claimed in  claim 9  wherein at least one of the internal walls meets an adjacent external wall at an angle α which is not greater than 60°.  
   
   
       13 . A finished turbine blade for a gas turbine engine, comprising a single-crystal casting of a metal alloy having a solvus temperature which is less than its incipient melting point, characterised in that the turbine blade has not been subjected to solution heat treatment after casting.  
   
   
       14 . A turbine blade as claimed in  claim 13  characterised in that the metal alloy is a NiAlX alloy in which X is one or more of hafnium, rhenium, titanium, chromium or gallium.  
   
   
       15 . A turbine blade as claimed in  claim 13  characterised in that the turbine blade is provided with cavities which are separated from adjacent cavities by internal walls and which are separated from the exterior of the turbine blade by external walls.  
   
   
       16 . A turbine blade as claimed in  claim 15  characterised in that the thickness of ratio Ti/Te of the internal and external walls is not greater than 1.5:1.  
   
   
       17 . A turbine blade as claimed in  claim 15  characterised in that at least one of the internal walls is provided with through holes, at least some of which are spaced apart by a spacing(s) which is not greater than 6 times the transverse dimension of the holes.  
   
   
       18 . A turbine blade as claimed in  claim 15  characterised in that at least one of the internal walls meets an adjacent external wall at an angle α which is not greater than 60°.  
   
   
       19 . A method of manufacturing a turbine blade for use in a gas turbine engine, the method comprising casting the turbine blade as a single crystal from a metal alloy, without a subsequent solution heat treatment step, said metal alloy having a solvus temperature less than its incipient melting point.