Components with near-surface cooling microchannels and methods for providing the same

Abstract

Methods for providing a near-surface cooling microchannel in a component include forming a near-surface cooling microchannel in a first surface of a pre-sintered preform, disposing the first surface of the pre-sintered preform onto an outer surface of the base article such that an opening of the outer surface of the base article is aligned with the near-surface cooling microchannel in the first surface of the pre-sintered preform, and, heating the pre-sintered preform to bond it to the base article, wherein the opening of the outer surface of the base article remains aligned with the near-surface cooling microchannel in the first surface of the pre-sintered preform.

What is claimed is: 
     
         1 . A method of providing a near-surface cooling microchannel in a component, the component comprising an internal cooling passage within a base article having an opening at an outer surface, the method comprising:
 forming a near-surface cooling microchannel in a first surface of a pre-sintered preform, wherein the pre-sintered preform comprises a mixture comprising a base alloy and a second alloy, the base alloy comprising about 30 weight percent to about 90 weight percent of the mixture and the second alloy comprising a sufficient amount of a melting point depressant to have a lower melting temperature than the base alloy;   disposing the first surface of the pre-sintered preform onto the outer surface of the base article such that the opening of the outer surface of the base article is aligned with the near-surface cooling microchannel in the first surface of the pre-sintered preform; and,   heating the pre-sintered preform to bond it to the base article, wherein the opening of the outer surface of the base article remains aligned with the near-surface cooling microchannel in the first surface of the pre-sintered preform.   
     
     
         2 . The method of  claim 1  further comprising forming a second near-surface cooling microchannel in the first surface of the pre-sintered preform, wherein when the pre-sintered preform is disposed on the outer surface of the base article, the second near-surface cooling microchannel aligns with a second opening in the outer surface of the base article. 
     
     
         3 . The method of  claim 1 , wherein the pre-sintered preform is formed by combining base alloy particles and second alloy particles with a binder to form a combined powder mixture, compacting the combined powder mixture to form a compacted preform, and heating the compacted preform to remove the binder and form the pre-sintered preform. 
     
     
         4 . The method of  claim 3 , wherein the near-surface cooling microchannel is formed into the compacted preform prior to heating. 
     
     
         5 . The method of  claim 1 , wherein the pre-sintered preform has a density of at least 90% of theoretical. 
     
     
         6 . The method of  claim 1 , wherein the base alloy and second alloy are mixed together at a weight ratio of about 30:70 to about 90:10, respectively. 
     
     
         7 . The method of  claim 1 , further comprising depositing a coating on an exterior surface of the pre-sintered preform, wherein the exterior surface is opposite the first surface. 
     
     
         8 . The method of  claim 7 , wherein the coating is deposited on the pre-sintered preform before the pre-sintered preform is bonded to the base article. 
     
     
         9 . The method of  claim 1  further comprising:
 disposing a filler material in the internal cooling passage prior to heating the pre-sintered preform; and, 
 removing the filler material from the internal cooling passage after heating the pre-sintered preform. 
 
     
     
         10 . The method of  claim 1 , wherein the pre-sintered preform is bonded to the outer surface of the base article without filling the opening. 
     
     
         11 . A component comprising:
 a base article comprising an internal cooling passage having an opening at an outer surface; and,   a pre-sintered preform having a first surface bonded to the outer surface of the base article, wherein the pre-sintered preform comprises a near-surface cooling microchannel in the first surface aligned with the opening of the outer surface of the base article, and wherein the pre-sintered preform comprises a mixture comprising a base alloy and a second alloy, the base alloy comprising about 30 weight percent to about 90 weight percent of the mixture and the second alloy comprising a sufficient amount of a melting point depressant to have a lower melting temperature than the base alloy.   
     
     
         12 . The component of  claim 11 , wherein the base article comprises a second opening at the outer surface, and wherein the pre-sintered preform comprises a second near-surface cooling microchannel aligned with the second opening. 
     
     
         13 . The component of  claim 11 , wherein the pre-sintered preform is formed by combining base alloy particles and second alloy particles with a binder to form a combined powder mixture, compacting the combined powder mixture to form a compacted preform, and heating the compacted preform to remove the binder and form the pre-sintered preform. 
     
     
         14 . The component of  claim 13 , wherein the near-surface cooling microchannel is formed into the compacted preform prior to heating. 
     
     
         15 . The component of  claim 11 , wherein the pre-sintered preform has a density of at least 90% of theoretical. 
     
     
         16 . The component of  claim 11 , wherein the base alloy and second alloy are mixed together at a weight ratio of about 30:70 to about 90:10, respectively. 
     
     
         17 . The component of  claim 11  further comprising a coating on an exterior surface of the pre-sintered preform, wherein the exterior surface is opposite the first surface. 
     
     
         18 . The component of  claim 11 , wherein the component comprises a hot gas path component for a turbine. 
     
     
         19 . The component of  claim 11 , wherein the near-surface cooling microchannel is disposed in both the first surface of the pre-sintered preform and the outer surface of the base article. 
     
     
         20 . The component of  claim 11 , wherein the base alloy and the base substrate share a common composition.