Mold assembly for use in a liquid metal cooled directional solidification furnace

Abstract

A mold assembly for a liquid metal cooled directional solidification furnace having a cooling chamber provided with liquid metal and a heating chamber includes a mold member having a main body portion that defines an interior mold cavity. The mold member is adapted to be positioned in the heating chamber. The mold assembly also includes a chill-plate formed from a material having a thermal diffusivity a 600° K greater than approximately 10 E-6 m2/s, inert to at least one of molten tin and molten aluminum and adapted to be at least partially immersed in the liquid metal. The chill-plate includes a main body portion having a first surface extending to a second surface through an intermediate portion. The chill-plate is adapted to establish a thermal gradient between the mold member and the heating chamber.

1 . A mold assembly for a liquid metal cooled directional solidification furnace having a cooling chamber provided with liquid metal and a heating chamber, the mold assembly comprising:
 a mold member having a main body portion that defines an interior mold cavity, the mold member being adapted to be positioned in the heating chamber; and   a chill-plate formed from a material having a thermal diffusivity at 600 K greater than approximately 10 E-6 m2/s, inert to at least one of molten tin and molten aluminum and adapted to be at least partially immersed in the liquid metal, the chill-plate including a main body portion having a first surface extending to a second surface through an intermediate portion, wherein the chill-plate is adapted to establish a thermal gradient between the mold member and the heating chamber.   
   
   
       2 . The mold assembly according to  claim 1 , wherein the chill-plate is formed from a material having a thermal diffusivity at 600° K greater than approximately 20 E-6 m´2/s. 
   
   
       3 . The mold assembly according to  claim 2 , wherein the chill-plate is formed from a material having a thermal diffusivity at 600° K greater than approximately 30 E-6 m´2/s. 
   
   
       4 . The mold assembly according to  claim 1 , wherein the chill-plate is formed from one of molybdenum, a molybdenum alloy, graphite, a graphite alloy, tungsten, a tungsten alloy and combinations thereof. 
   
   
       5 . The mold assembly according to  claim 1 , wherein the main body portion of the chill-plate has a thickness of up to approximately 12 inches (30.48 cm) 
   
   
       6 . The mold assembly according to  claim 5 , wherein the main body portion of the chill-plate has a thickness of between approximately 3 inches (7.62 cm) and approximately 5 inches (12.7 cm). 
   
   
       7 . The mold assembly according to  claim 6 , wherein the main body portion of the chill-plate has a thickness of approximately 4 inches (10.16 cm). 
   
   
       8 . A liquid metal cooled directional solidification furnace comprising:
 a heating portion including a heating chamber having a first temperature;   a cooling portion including a cooling chamber provided with liquid metal having a second temperature, the second temperature being less than the first temperature; and   a mold assembly positioned in each of the heating portion and cooling portion, the mold assembly including:   a mold member having a main body portion that defines an interior mold cavity, the mold member being positioned in the heating chamber; and   a chill-plate formed from a material having a thermal diffusivity at 600° K greater than approximately 10 E-6 m2/s and at least partially immersed in the liquid metal, the chill-plate including a main body portion having a first extending to a second surface through an intermediate portion, wherein the chill-plate, partially immersed in the liquid metal, establishes a thermal gradient between the mold member and the heating chamber.   
   
   
       9 . The mold assembly according to  claim 8 , wherein the chill-plate is plate is formed from a material having a thermal diffusivity at 600° K greater than approximately 20 E-6 m´2/s. 
   
   
       10 . The mold assembly according to  claim 9 , wherein the chill-plate plate is formed from a material having a thermal diffusivity at 600° K greater than approximately 30 E-6 m´2/s. 
   
   
       11 . The mold assembly according to  claim 8 , wherein the chill-plate is formed from one of molybdenum, a molybdenum alloy, graphite, a graphite alloy, tungsten, a tungsten alloy, and combinations thereof. 
   
   
       12 . The liquid cooled directional solidification furnace according to  claim 8 , wherein the main body portion of the chill-plate has a thickness of up to approximately 12 inches (30.48 cm). 
   
   
       13 . The liquid cooled directional solidification furnace according to  claim 12 , wherein the main body portion of the chill-plate has a thickness of between 3 inches (7.62 cm) and approximately 5 inches (12.7 cm). 
   
   
       14 . The liquid cooled directional solidification furnace according to  claim 13 , wherein the main body portion of the chill-plate has a thickness of approximately 4 inches (10.16 cm). 
   
   
       15 . The liquid cooled directional solidification furnace according to  claim 8 , wherein the liquid metal includes tin. 
   
   
       16 . The liquid cooled directional solidification furnace according to  claim 8 , wherein the liquid metal is aluminum. 
   
   
       17 . A method of forming a cast component in a liquid metal cooled directional solidification furnace comprising:
 supporting a portion of a mold assembly upon a chill-plate formed from a material having a thermal diffusivity at 600° K greater than approximately 10 E-6 m2/s into a liquid cooled directional solidification furnace;   positioning a the mold member in a heating chamber having a first temperature and a portion of the chill-plate into a liquid metal bath having a second temperature, the second temperature being higher than the first temperature;   raising the temperature in the heating chamber from the first temperature to a third temperature, the third temperature being substantially higher than the second temperature; and   maintaining the portion of the mold member supported upon the chill-plate at a fourth temperature, the fourth temperature being substantially less than the third temperature.   
   
   
       18 . The method of  claim 17 , wherein support a portion of the mold member upon a chill-plate formed from a material having a thermal diffusivity at 600° K greater than approximately 10 E-6 m2/s includes supporting a portion of the mold member on a chill-plate formed from at least one of molybdenum, a molybdenum alloy, graphite, a graphite alloy, tungsten, a tungsten alloy and combinations thereof. 
   
   
       19 . The method of  claim 17 , further comprising: maintaining a temperature variation within the chill-plate between approximately 482° F. (250° C.) and 1022° F. (550° C.).