Anvil for friction stir welding high temperature materials

Abstract

A friction stir welding anvil and method of producing a friction stir welding anvil that precludes diffusion or mechanical bonding of the anvil to the work pieces are provided. The alternatives for producing such an anvil comprise coating the anvil with diffusion barriers such as oxides, nitrides, intermetallics, and/or refractory metals; manufacturing an anvil either completely or partially from the same; or placing a coating of such materials in the form of a thin sheet or a powder between the anvil and the work pieces. The anvil disclosed herein exhibits high strength and hardness even at elevated temperatures, such as those greater than 800° C., so as to prevent the anvil from mechanically or diffusion bonding to the work pieces and so as to minimize, or eliminate altogether, anvil deformation.

1 . An anvil that is configured for use in friction stir welding, the anvil comprising: 
 a core configured to support materials being welded together by a friction stir welding process; and    a chemically inert material that is included in one of: 
 (i) the core; and  
 (ii) a coating applied onto at least a portion of the core.  
   
   
   
       2 . An anvil as recited in  claim 1 , wherein the coating comprises one of: 
 (i) an element selected from group IIIA of the periodic table of elements;    (ii) an element selected from group IVA of the periodic table of elements;    (iii) an element selected from group IVAB of the periodic table of elements;    and    (iv) an element selected from group IVB of the periodic table of elements.    
   
   
       3 . An anvil as recited in  claim 1 , wherein the coating comprises one of: 
 (i) a diamond;    (ii) an intermetallic; and    (iii) a refractory metal.    
   
   
       4 . An anvil as recited in  claim 1 , wherein the anvil forms a diffusion barrier between the materials being welded together and a surface of the anvil when performing a friction stir welding process.  
   
   
       5 . An anvil as recited in  claim 1 , wherein the anvil enables full penetration of welding the materials.  
   
   
       6 . An anvil as recited in  claim 1 , wherein the anvil resists deformation during the friction stir welding process.  
   
   
       7 . An anvil as recited in  claim 1 , wherein the anvil prevents mechanical bonding between the materials and the anvil.  
   
   
       8 . An anvil as recited in  claim 1 , wherein the chemically inert material comprises one of: 
 (i) an oxide;    (ii) a nitride;    (iii) a carbide; and    (iv) a silicate.    
   
   
       9 . An anvil as recited in  claim 1 , wherein the core is one of: 
 (i) a plate; and    (ii) a rotating wheel.    
   
   
       10 . A method for manufacturing a friction stir welding anvil that is capable of friction stir welding high temperature materials, the method comprising the steps for: 
 providing an anvil core that is configured to support materials being welded together by a friction stir welding process; and    using a chemically inert material in providing one of: 
 (i) the anvil core; and  
 (ii) a coating on at least a portion of the core.  
   
   
   
       11 . A method as recited in  claim 10 , wherein the step for using a chemically inert material comprises one of the steps for: 
 (i) using a spray-coating process;    (ii) using a deposition process;    (iii) using an anodizing process;    (iv) using an ion beam sintering process;    (v) using a slurry process; and    (vi) using a chemical reaction process.    
   
   
       12 . A method as recited in  claim 10 , wherein the step for using comprises the step for coating at least a portion of the core using a powder coating process, and wherein the chemically inert material is in a power form.  
   
   
       13 . A method as recited in  claim 10 , wherein the chemically inert material comprises a metal and oxygen.  
   
   
       14 . A method as recited in  claim 10 , wherein the chemically inert material comprises a metal and nitrogen.  
   
   
       15 . A method as recited in  claim 10 , wherein the chemically inert material comprises a metal and carbon.  
   
   
       16 . A method as recited in  claim 10 , wherein the chemically inert material comprises a metal and silicon.  
   
   
       17 . A method as recited in  claim 10 , further comprising the step for forming the core into one of: 
 (i) a flat plate; and    (iii) a rotating wheel.    
   
   
       18 . A method for providing an anvil for use in friction stir welding, the method comprising the steps for: 
 providing an anvil having a core;    placing materials that are to be friction stir welded onto the anvil;    friction stir welding the materials; and    monitoring the temperature of the weld.    
   
   
       19 . A method as recited in  claim 18 , wherein the step for providing includes the steps for: 
 forming a cavity in the core; and    attaching a conduit to the cavity.    
   
   
       20 . A method as recited in  claim 19 , wherein the step for monitoring the temperature of the weld comprises the step for circulating a fluid through the cavity to regulate the temperature of the anvil.