Minimization of Re-Crystallization in Single Crystal Castings

Abstract

A refractory metal core for forming internal features in a turbine engine component has a core formed from a refractory metal material; and the core has at least one blended surface on at least one edge of the core.

1 . A refractory metal core for forming internal features in a turbine engine component, comprising:
 a core formed from a refractory metal material; and   said core having at least one blended surface on at least one edge of said core, wherein said core has two opposed edges and each said edge has a blended surface, wherein each said edge has a radius and said refractory metal core has a length which forms a radius/length ratio in the range of from 0.0094:1 to 0.156:1.   
     
     
         2 . The refractory metal core of  claim 1 , wherein said core has a longitudinal axis and said at least one blended surface extends substantially parallel to said longitudinal axis. 
     
     
         3 - 4 . (canceled) 
     
     
         5 . The refractory metal core of  claim 1 , wherein said radius/length ratio is in the range of from 0.025:1 to 0.156:1. 
     
     
         6 . The refractory metal core of  claim 1 , wherein said refractory metal core has a radius to thickness ratio in the range of 0.28:1 to 0.4:1. 
     
     
         7 . The refractory metal core of  claim 1 , wherein said core has two lateral surfaces and said at least one blended surface extends between said two lateral surfaces. 
     
     
         8 . The refractory metal core of  claim 1 , wherein said at least one blended surface comprises a curved surface. 
     
     
         9 . The refractory metal core of  claim 1 , wherein said at least one blended surface extends 180 degrees. 
     
     
         10 . A molding system for forming a turbine engine component comprising:
 a mold;   at least one ceramic core placed within the mold to form an internal passageway in said turbine engine component; and   at least one refractory metal core placed within the mold to form an internal feature in at least one wall of said turbine engine component,   wherein said at least one refractory metal core has at least one edge with at least one blended surface, wherein said at least one refractory metal core has two opposed edges and each edge has a blended surface, wherein each said edge has a radius and said refractory metal core has a length which forms a radius/length ratio in the range of from 0.0094:1 to 0.156:1.   
     
     
         11 . The molding system of  claim 10 , wherein a plurality of ceramic cores are placed in said mold. 
     
     
         12 . The molding system of  claim 10 , wherein a plurality of refractory metal cores are placed in said mold. 
     
     
         13 . The molding system of  claim 10 , wherein said at least one refractory metal core has a longitudinal axis and said at least one blended surface extends substantially parallel to said longitudinal axis. 
     
     
         14 - 15 . (canceled) 
     
     
         16 . The molding system of  claim 10 , wherein said radius/length ratio is in the range of from 0.025:1 to 0.156:1. 
     
     
         17 . The molding system of  claim 10 , wherein said refractory metal core has a radius to thickness ratio in the range of 0.28:1 to 0.4:1. 
     
     
         18 . The molding system of  claim 13 , wherein said at least one refractory metal core has two lateral surfaces and said at least one blended surface extends between said two lateral surfaces. 
     
     
         19 . The molding system of  claim 10 , wherein said at least one blended surface comprises a curved surface. 
     
     
         20 . The molding system of  claim 19 , wherein said at least one blended surface extends 180 degrees. 
     
     
         21 . A process for casting a turbine engine component, comprising:
 providing a mold;   placing at least one ceramic core within the mold to form an internal passageway in said turbine engine component; and   placing at least one refractory metal core within the mold to form an internal feature in at least one wall of said turbine engine component,   wherein said at least one refractory metal core has at least one edge with at least one blended surface,   further comprising providing said refractory metal core with two opposed edges and each edge has a blended surface and   further comprising providing each said edge with a radius and providing said refractory metal core with a length which forms a radius/length ratio in the range of from 0.0094:1 to 0.156:1.   
     
     
         22 . The process of  claim 21 , wherein said at least one ceramic core placing step comprises placing a plurality of ceramic cores in said mold. 
     
     
         23 . The process of  claim 21 , wherein said at least one refractory metal core step comprises placing a plurality of refractory metal cores in said mold. 
     
     
         24 . The process of  claim 21 , further comprising providing said refractory metal core with a longitudinal axis and said at least one blended surface extending substantially parallel to said longitudinal axis. 
     
     
         25 - 26 . (canceled) 
     
     
         27 . The process of  claim 21 , wherein said radius/length ratio is in the range of from 0.025:1 to 0.156:1. 
     
     
         28 . The process of  claim 21 , further comprising providing said refractory metal core with a radius to thickness ratio in the range of 0.28:1 to 0.4:1. 
     
     
         29 . The process of  claim 21 , further comprising providing said core with two lateral surfaces and said at least one blended surface extending between said two lateral surfaces. 
     
     
         30 . The process of  claim 21 , further comprising forming said at least one blended surface as a curved surface. 
     
     
         31 . The process of  claim 21 , further comprising forming said at least one blended surface to extend 180 degrees. 
     
     
         32 . The process of  claim 21 , further comprising pouring metal in said mold to form said turbine engine component. 
     
     
         33 . The process of  claim 32 , further comprising removing said at least one ceramic core and said at least one refractory core.