Single piece casting of reactive alloys

Abstract

A method of vacuum induction melting a charge of material includes preheating a mold; inserting the charge into the mold; placing the mold into a chamber; reducing an operating pressure within the chamber; induction melting the charge within the mold; allowing material of the charge to fill a cavity defined within the mold; applying electromagnetic pressure to the charge within the mold; and applying an electromagnetic field to material of the charge positioned within the cavity defined within the mold.

1 . A method of vacuum induction melting a charge of material and casting an article, comprising:
 preheating a mold;   inserting the charge into the mold;   placing the mold into a chamber;   reducing an operating pressure within the chamber;   induction melting the charge within the mold;   applying electromagnetic pressure to the charge within the mold;   allowing material of the charge to fill a cavity defined within the mold to form the article; and   applying an electromagnetic field to material of the charge positioned within the cavity defined within the mold.   
     
     
         2 . The method of  claim 1 , further comprising preheating the charge. 
     
     
         3 . The method of  claim 1 , wherein the mold comprises a ceramic material. 
     
     
         4 . The method of  claim 1 , wherein the mold comprises a graphite material. 
     
     
         5 . The method of  claim 1 , wherein the mold comprises a ceramic and a graphite material. 
     
     
         6 . The method of  claim 1 , wherein the charge comprises a reactive alloy. 
     
     
         7 . The method of  claim 6 , wherein the charge comprises a titanium alloy. 
     
     
         8 . The method of  claim 6 , wherein the charge comprises a titanium aluminide alloy. 
     
     
         9 . The method of  claim 1 , wherein the chamber comprises a quartz chamber. 
     
     
         10 . The method of  claim 1 , wherein applying magnetic pressure comprises manipulating a time dependent electromagnetic field. 
     
     
         11 . The method of  claim 10 , wherein applying magnetic pressure comprises manipulating a time dependent electromagnetic field during a melting of the charge. 
     
     
         12 . The method of  claim 10 , wherein applying magnetic pressure comprises manipulating a time dependent electromagnetic field during a flowing of the charge into the cavity. 
     
     
         13 . The method of  claim 10 , wherein applying magnetic pressure comprises manipulating a time dependent electromagnetic field during a solidification of the charge. 
     
     
         14 . The method of  claim 1 , wherein applying magnetic pressure comprises manipulating electromagnetic field gradients 
     
     
         15 . The method of  claim 1 , wherein applying electromagnetic pressure comprises applying a stronger electromagnetic field to an upper portion of the charge than to a lower portion of the charge. 
     
     
         16 . The method of  claim 1 , wherein applying electromagnetic pressure comprises locating the charge within a non uniform electromagnetic field. 
     
     
         17 . The method of  claim 1 , further comprising:
 allowing the material of the charge to solidify within the cavity in the presence of an applied electromagnetic field   
     
     
         18 . The method of  claim 17 , wherein the solidified material comprises a symmetrical structure. 
     
     
         19 . The method of  claim 17 , wherein the solidified material comprises an asymmetrical structure. 
     
     
         20 . The method of  claim 17 , wherein the solidified material does not include detectable gas porosity using conventional gas porosity detection methods. 
     
     
         21 . The method of  claim 17 , wherein the solidified material does not include inclusions using conventional inclusion detection methods. 
     
     
         22 . The method of  claim 17 , wherein the solidified material comprises a fully lamellar microstructure. 
     
     
         23 . The method of  claim 22 , wherein the material comprises a titanium aluminide alloy. 
     
     
         24 . The method of  claim 17 , wherein the solidified material comprises a hub and one or more blades that extend in a radial direction from the hub. 
     
     
         25 . The method of  claim 17 , wherein the solidified material comprises a turbine wheel. 
     
     
         26 . The method of  claim 17 , wherein the solidified material comprises a compressor wheel. 
     
     
         27 . A method for vacuum induction melting a charge of material and casting an article, comprising:
 providing a ceramic mold which comprises a cup which communicates with a cavity defined within the mold for defining a shape of a part;   providing a reactive alloy charge;   preheating the mold;   placing the charge of material within the preheated cup of the mold;   applying a time dependent electromagnetic field to the mold;   inducing electrical eddy currents within the reactive alloy charge;   generating an electromagnetic field which is opposed to the applied time dependent electromagnetic field and creating repulsive pressures on the reactive alloy charge;   manipulating the time dependent applied electromagnetic field and applying greater magnetic pressure on a top portion of the reactive alloy charge relative to a bottom portion of the reactive alloy charge;   melting at least a portion of the reactive alloy charge;   electromagnetically stirring the melted portion of the reactive alloy charge;   forcing the melted portion of the reactive alloy charge into at least a portion of the cavity of the mold using the magnetic pressures to form the article; and   applying an electromagnetic field to the melted portion of the reactive alloy charge within the cavity of the mold.   
     
     
         28 . The method of  claim 27 , further comprising allowing the melted portion of the reactive alloy charge to solidify within the cavity of the mold. 
     
     
         29 . The method of  claim 28 , further comprising applying an electromagnetic field to the solidified portion of the reactive alloy charge within the cavity of the mold. 
     
     
         30 . The method of  claim 29 , further comprising controlling and modifying a structure of the solidified portion of the reactive alloy within the cavity of the mold. 
     
     
         31 . The method of  claim 29 , wherein applying the electromagnetic field to the solidified portion of the reactive alloy charge within the cavity of the mold comprises heat treating the solidified portion of the reactive alloy within the cavity of the mold.