Method of manufacturing a component by consolidating a metal powder

Abstract

A method of manufacturing a component ( 10,20 ) by consolidating a metal powder comprises preparing a metal powder, the metal powder comprising metal particles ( 30 ). Depositing a coating ( 32 ) containing at least one element on the surfaces ( 34 ) of the metal particles ( 30 ) of the metal powder. Applying heat and pressure to consolidate the metal particles ( 30 ) such that the at least one element of the coating ( 32 ) on the surfaces ( 34 ) of the metal particles ( 30 ) partially diffuses into the metal particles ( 30 ) and the coated metal particles ( 30 ) are diffusion bonded together to form a cellular structure ( 36 ).

1 . A method of manufacturing a component by consolidating a metal powder comprising the steps of: 
 (d) preparing a metal powder, the metal powder comprising metal particles,    (e) depositing a coating containing at least one element on the surfaces of the metal particles of the metal powder,    (f) applying heat and pressure to consolidate the metal particles such that the at least one element of the coating on the surfaces of the metal particles partially diffuse into the metal particles and the coated metal particles are diffusion bonded together to form a cellular structure, the cellular structure comprising a framework of more highly alloyed material located at the boundaries of the diffusion bonded metal particles and the centres of the consolidated metal particles retain their original composition.    
   
   
       2 . A method as claimed in  claim 1  wherein step (b) comprises oxidising the surfaces of the metal particles.  
   
   
       3 . A method as claimed in  claim 1  wherein step (b) comprises nitriding the surfaces of the metal particles.  
   
   
       4 . A method as claimed in  claim 1  wherein step (b) comprises vapour depositing a solid solution strengthening element on the surfaces of the metal particles.  
   
   
       5 . A method as claimed in  claim 1  wherein step (b) comprises coating the surfaces of the metal particles with a second metal having lower melting point than the metal particles.  
   
   
       6 . A method as claimed in  claim 1  wherein step (b) comprises coating the surfaces of the metal particles with particles of a second metal powder having a lower yield strength than the metal particles.  
   
   
       7 . A method as claimed in  claim 1  wherein the metal particles are alloy particles.  
   
   
       8 . A method as claimed in  claim 5  wherein the second metal is an alloy.  
   
   
       9 . A method as claimed in  claim 6  wherein the second metal particles are alloy particles.  
   
   
       10 . A method as claimed in  claim 7  wherein the metal particles are titanium alloy particles.  
   
   
       11 . A method as claimed in  claim 10  wherein the titanium alloy particles comprise 6 wt % aluminium, 4 wt % vanadium and the balance titanium, minor additions and incidental impurities.  
   
   
       12 . A method as claimed in  claim 11  wherein step a) comprises supplying the titanium alloy particles into a container, step b) comprises oxidising the titanium alloy particles, step c) comprises sealing the container and applying heat and pressure.  
   
   
       13 . A method as claimed in  claim 12  wherein step b) comprises heating to a temperature of 450° C. and maintaining at 450° C. for 8 hours under a partial pressure of 10 −1  torr to oxidise the titanium alloy particles and step c) comprises hot isostatic pressing the container at a temperature of 925° C. for 2 hours at a pressure of 150 MPa.  
   
   
       14 . A method as claimed in  claim 12  wherein the container is removed by machining or dissolving in a suitable acid.  
   
   
       15 . A method as claimed in  claim 12 , wherein the container comprises mild steel.  
   
   
       16 . A method as claimed in  claim 1  wherein the metal particles have an average size of 100 micrometers.  
   
   
       17 . A method as claimed in  claim 1  wherein the metal particles have a maximum size of 250 micrometers.  
   
   
       18 . A method as claimed in  claim 1  wherein the size of the metal particles is varied to vary the properties of the component.  
   
   
       19 . A component comprising consolidated metal powder, the metal powder comprising metal particles diffusion bonded together, the surfaces of the metal particles having a coating having at least one element, which has partially diffused into the metal particles to form a cellular structure, the cellular structure comprising a framework of more highly alloyed material located at the boundaries of the diffusion bonded metal particles and the centres of the consolidated metal particles retain their original composition.  
   
   
       20 . A component as claimed in  claim 19  wherein the coating is selected from the group comprising an oxide and a nitride and the at least one element is oxygen or nitrogen respectively.  
   
   
       21 . A component as claimed in  claim 19  wherein the coating comprises a solid solution strengthening element on the surfaces of the metal particles.  
   
   
       22 . A component as claimed in  claim 19  wherein the coating comprises a second metal having lower melting point than the metal particles.  
   
   
       23 . A component as claimed in  claim 19  wherein the coating comprises a second metal powder having a lower yield strength than the metal particles.  
   
   
       24 . A component as claimed in  claim 19  wherein the metal particles are titanium alloy particles.  
   
   
       25 . A component as claimed in  claim 24  wherein the titanium alloy particles comprise 6 wt % aluminium, 4 wt % vanadium and the balance titanium, minor additions and incidental impurities.  
   
   
       26 . A component as claimed in  claim 20  wherein the component is a gas turbine engine component.  
   
   
       27 . A component as claimed in  claim 26  wherein the component is a fan blade, a part of a fan blade, a compressor blade or a casing.