System and method for additive manufacturing

Abstract

A method for forming a component includes providing a first layer of a mixture of first and second powders. The method includes determining the frequency of an alternating magnetic field to induce eddy currents sufficient to bulk heat only one of the first and second powders. The alternating magnetic field is applied at the determined frequency to a portion of the first layer of the mixture using a flux concentrator. Exposure to the magnetic field changes the phase of at least a portion of the first powder to liquid. The liquid portion couples to at least some of the second powder and subsequently solidifies to provide a composite component.

What is claimed is: 
     
         1 . A method for forming a component comprising:
 providing a first layer of a mixture of first and second powders;   determining a frequency of an alternating magnetic field to induce eddy currents sufficient to (i) bulk heat only the first powder and bulk heating of particles of the first powder occurs when a diameter of each of a plurality of particles of the first powder is at least equal to 2δ for the respective particle of the first powder, wherein:   
       
         
           
             
               f 
               = 
               
                 
                   4 
                    
                   
                       
                   
                    
                   ρ 
                 
                 
                   π 
                    
                   
                       
                   
                    
                   μ 
                    
                   
                       
                   
                    
                   
                     d 
                     2 
                   
                 
               
             
           
         
         where d is the diameter of a respective particle of the first powder, ρ is the resistivity of the material of a respective particle of the first powder, f is the frequency of the alternating magnetic field, and μ is the magnetic permeability of the material of the respective particle of the first powder and (ii) surface heat particles of the second powder; and 
         applying the alternating magnetic field at the determined frequency to the first layer of the mixture using a flux concentrator, wherein exposure to the magnetic field changes the phase of at least a portion of the first powder to liquid by bulk heating the particles of the first powder and heating the particles of the second powder such that outer regions of the particles of the second powder change phase to liquid while inner regions of the particles of the second powder remain solid. 
       
     
     
         2 . The method of  claim 1 , wherein two or more particles of the first powder combine to form a consolidated material after the two or more particles change to the liquid phase, the consolidated material having a size de-coupling the magnetic field from the consolidated material. 
     
     
         3 . The method of  claim 1 , wherein surface heating of each particle of the second powder occurs when 2δ for the respective particle of the second powder is less than a diameter of the respective particle of the second powder. 
     
     
         4 . The method of  claim 1 , wherein determining the frequency of the alternating magnetic field is based on a dimension of the particles within the first powder. 
     
     
         5 . The method according to  claim 4 , wherein the first powder has a first mean particle diameter and the second powder has a second mean particle diameter which is different from the first mean particle diameter. 
     
     
         6 . The method of  claim 1 , wherein determining the frequency of the alternating magnetic field is based on a resistivity of particles with the first powder. 
     
     
         7 . The method according to  claim 6 , wherein the first material has a first resistivity and the second material has a second resistivity different than the first resistivity. 
     
     
         8 . The method according to  claim 1 , wherein the first powder includes particles from a first material and the second powder includes particles from a different second material. 
     
     
         9 . The method according to  claim 8 , wherein the first material is a metal and the second material is carbon fiber. 
     
     
         10 . The method according to  claim 8 , wherein the first material is WC and the second material is cobalt. 
     
     
         11 . The method according to  claim 8 , wherein the first material is a metal and the second material is a ceramic. 
     
     
         12 . The method according to  claim 1 , further comprising applying a second layer of powder material over the first layer of powder material and applying the magnetic field to the second layer. 
     
     
         13 . The method according to  claim 1 , further comprising ceasing to apply the magnetic field to solidify the liquid portion and couple a portion of the first powder with portions of the second powder.