Article for use in high stress environments having multiple grain structures

Abstract

A method of forming an article can comprise heating a metal to form a molten metal having a metal temperature; heating a mold to a mold temperature greater than or equal to the metal temperature; introducing the molten metal to the mold; cooling a first portion of the molten metal while maintaining a second portion of the molten metal at the metal temperature, wherein the first portion has a first side and a second side, wherein the second side is opposite the first side and adjacent to the second portion, and wherein the cooling comprises progressively cooling the first portion from the first side to the second side such that a solidification interface progresses from the first side to the second side; and cooling the remainder of the molten metal from multiple directions after the first portion is cooled to less than or equal to a crystallization temperature.

1 . A method of forming an article comprising:
 heating a metal to form a molten metal having a metal temperature;   heating a mold to a mold temperature greater than or equal to the metal temperature;   introducing the molten metal to the mold;   cooling a first portion of the molten metal while maintaining a second portion of the molten metal at the metal temperature, wherein the first portion has a first side and a second side, wherein the second side is opposite the first side and adjacent to the second portion, and wherein the cooling comprises progressively cooling the first portion from the first side to the second side such that a solidification interface progresses from the first side to the second side; and   cooling the remainder of the molten metal from multiple directions after the first portion is cooled to less than or equal to a crystallization temperature.   
     
     
         2 . The method of  claim 1 , wherein cooling the remainder of the molten metal further comprises cooling the molten metal from all mold surfaces. 
     
     
         3 . The method of  claim 1 , wherein a volume of the first portion is greater than or equal 20% of a total volume of the article. 
     
     
         4 . The method of  claim 1 , comprising determining a higher stress area of the article. 
     
     
         5 . The method of  claim 4 , wherein the higher stress area is within the first portion. 
     
     
         6 . A part for a turbine made by the method of  claim 1 . 
     
     
         7 . A part for a turbine comprising:
 a base having a base wall and an attachment;   an airfoil extending from the base wall;   wherein the part comprises a first portion comprising the base and a first section of the airfoil and a second portion comprising a second section of the airfoil, wherein the first portion comprises a metal having directionally solidified grains and the second portion comprises the metal having equiaxed grains.   
     
     
         8 . The part of  claim 7 , comprising a shroud having a shroud wall, wherein the airfoil extends between the base and the shroud wall, and wherein the second portion further comprises the shroud. 
     
     
         9 . The part of  claim 7 , wherein the first portion comprises a first portion volume and wherein the first portion volume is less than or equal to 60% of a total volume of the part. 
     
     
         10 . The part of  claim 7 , wherein the metal is a metal alloy, and wherein the metal alloy comprises GTD111, GTD222, GTD262, Mar M247, IN 738, Rene 80, IN 939, Rene N2, Rene 108, or a combination comprising at least one of the foregoing. 
     
     
         11 . The part of  claim 7 , wherein the metal is a metal alloy, and wherein the metal alloy comprises 7.5 to 9.0 weight percent Cr, 9.5 to 10.5 weight percent Co, 5.0 to 6.0 weight percent Al, 0.50 to 1.5 weight percent Ti, 0.2 to 1 weight percent Mo, 2 to 4 weight percent Ta, 9 to 11 weight percent W, 1 to 2 weight percent Hf, 0.025 to 0.075 weight percent Zr, 0.010 to 0.020 weight percent B, 0.10 to 0.20 weight percent C, and the balance Ni. 
     
     
         12 . The part of  claim 7 , wherein the metal is a metal alloy, and wherein the metal alloy comprises 13 to 15 weight percent Cr, 9 to 10 weight percent Co, 2 to 4 weight percent Al, 4 to 6 weight percent Ti, 1 to 3 weight percent Mo, 2 to 4 weight percent Ta, 3 to 5 weight percent W, 0.01 to 0.03 weight percent Zr, 0.008 to 0.02 weight percent B, 0.050 to 0.20 weight percent C, and the balance Ni. 
     
     
         13 . The part of  claim 7 , wherein the metal is a metal alloy, and wherein the metal alloy comprises 19 to 25 weight percent Cr, 12 to 21 weight percent Co, 1.5 to 3.5 weight percent Al, 1.0 to 3.9 weight percent Ti, 0.050 to 3.0 weight percent Ta, 0.050 to 3.5 weight percent W, 0.0050 to 0.050 weight percent Zr, 0.0010 to 0.060 weight percent B, 0.050 to 0.20 weight percent C, 0.05 to 2 weight percent Nb, and the balance Ni. 
     
     
         14 . The part of  claim 7 , wherein the metal is a metal alloy, and wherein the metal alloy comprises 15.5 to 17.5 weight percent Cr, 7 to 9 weight percent Co, 1 to 5 weight percent Al, 2.5 to 6.0 weight percent Ti, 0.50 to 3.0 weight percent Mo, 0.70 to 3.0 weight percent Ta, 0.050 to 3.5 weight percent W, 0.0050 to 0.15 weight percent Zr, 0.0010 to 0.060 weight percent B, 0.050 to 0.20 weight percent C, 0.05 to 2 weight percent Nb, and the balance Ni. 
     
     
         15 . The part of  claim 7 , wherein the metal is a metal alloy, and wherein the metal alloy comprises 13 to 15 weight percent Cr, 7.0 to 11 weight percent Co, 1 to 5 weight percent Al, 2.5 to 6.0 weight percent Ti, 3.1 to 6 weight percent Mo, 2 to 6 weight percent W, 0.0050 to 0.15 weight percent Zr, 0.0010 to 0.060 weight percent B, 0.050 to 0.20 weight percent C, and the balance Ni.