Semi-passive control of solidification in powdered materials

Abstract

Disclosed herein are surface-functionalized powders which alter the solidification of the melted powders. Some variations provide a powdered material comprising a plurality of particles fabricated from a first material, wherein each of the particles has a particle surface area that is continuously or intermittently surface-functionalized with nanoparticles and/or microparticles selected to control solidification of the powdered material from a liquid state to a solid state. Other variations provide a method of controlling solidification of a powdered material, comprising melting at least a portion of the powdered material to a liquid state, and semi-passively controlling solidification of the powdered material from the liquid state to a solid state. Several techniques for semi-passive control are described in detail. The methods may further include creating a structure through one or more techniques selected from additive manufacturing, injection molding, pressing and sintering, capacitive discharge sintering, or spark plasma sintering.

What is claimed is: 
     
         1 . A method of controlling solidification of a powdered material, said method comprising:
 providing a powdered material comprising a plurality of particles, wherein said particles are fabricated from a first material, and wherein each of said particles has a particle surface area that is surface-functionalized with a second material containing nanoparticles and/or microparticles;   melting at least a portion of said powdered material to a liquid state; and   semi-passively controlling solidification of said powdered material from said liquid state to a solid state.   
     
     
         2 . The method of  claim 1 , wherein at least 2 vol % of said powdered material is melted to form said liquid state. 
     
     
         3 . The method of  claim 1 , wherein said semi-passively controlling solidification includes nucleation control. 
     
     
         4 . The method of  claim 1 , wherein said semi-passively controlling solidification includes thermodynamic control. 
     
     
         5 . The method of  claim 1 , wherein said semi-passively controlling solidification includes thermal conductivity control. 
     
     
         6 . The method of  claim 1 , wherein said semi-passively controlling solidification includes eutectic or peritectic reaction control. 
     
     
         7 . The method of  claim 1 , wherein said semi-passively controlling solidification includes rejection of contaminants reacted with said nanoparticles and/or microparticles. 
     
     
         8 . The method of  claim 1 , wherein said solid state is a three-dimensional microstructure containing said nanoparticles and/or microparticles as inclusions distributed throughout said solid state. 
     
     
         9 . The method of  claim 1 , wherein said solid state is a layered microstructure containing one or more layers comprising said nanoparticles and/or microparticles. 
     
     
         10 . The method of  claim 1 , wherein said particles, prior to said melting, are present as a loose powder, a paste, a suspension, a green body, or a combination thereof. 
     
     
         11 . The method of  claim 1 , wherein said particles have an average particle size from about 1 micron to about 1 centimeter. 
     
     
         12 . The method of  claim 1 , wherein said particles are fabricated from a first material selected from the group consisting of ceramic, metal, polymer, glass, and combinations thereof. 
     
     
         13 . The method of  claim 1 , wherein said nanoparticles and/or microparticles are fabricated from a second material selected from the group consisting of metal, ceramic, polymer, carbon, and combinations thereof. 
     
     
         14 . The method of  claim 1 , said method further comprising creating a structure through one or more techniques selected from the group consisting of additive manufacturing, injection molding, pressing and sintering, capacitive discharge sintering, and spark plasma sintering.