Apparatus and method for manufacturing a turbocharger component

Abstract

A method of pressure casting a turbocharger component for an internal combustion engine may include heating an aluminum-scandium alloy to form a molten casting material including up to about 5 wt % scandium that is fully dissolved in the molten casting material, and introducing the molten casting material into a cavity of a mold from a bottom of the mold toward a top of the mold while applying a pressure to the molten casting material with a movable portion of a ram positioned in contact with the bottom of the mold. The method may also include solidifying the molten casting material by cooling the casting material as it comes into contact with a cooling member positioned on the top of the mold, wherein a coolant is pumped through coolant passages formed in the cooling member in order to cool the casting material at a cooling rate such that the solidifying preserves at least 70% of an original amount of the scandium in the aluminum-scandium alloy in solid solution in the casting material. The method may still further include removing the solidified casting material from the mold, and forming scandium precipitates within the casting material by aging the casting material at an aging temperature.

What is claimed is: 
     
         1 . A method of pressure casting a turbocharger component for an internal combustion engine, the method comprising:
 heating an aluminum-scandium alloy to form a molten casting material including up to about 5 wt % scandium that is fully dissolved in the molten casting material;   introducing the molten casting material into a cavity of a mold from a bottom of the mold toward a top of the mold while applying a pressure to the molten casting material with a movable portion of a ram positioned in contact with the bottom of the mold;   solidifying the molten casting material by cooling the casting material as it comes into contact with a cooling member positioned on the top of the mold, wherein a coolant is pumped through coolant passages formed in the cooling member in order to cool the casting material at a cooling rate such that the solidifying preserves at least 70% of an original amount of the scandium in the aluminum-scandium alloy in solid solution in the casting material;   removing the solidified casting material from the mold; and   forming scandium precipitates within the casting material by aging the casting material at an aging temperature.   
     
     
         2 . The method of  claim 1 , wherein the cooling rate is between about 5° C. per second and 200° C. per second. 
     
     
         3 . The method of  claim 1 , wherein the aluminum-scandium alloy comprises:
 1 to 4 wt % copper;   0 to 3 wt % magnesium;   0 to 7 wt % zinc;   0 to 2 wt % nickel;   0 to 2 wt % iron; and at least one of the following alloying elements:
 up to about 2 wt % scandium; 
 0 to 2 wt % zirconium; and 
 0 to 1 wt % titanium, with the balance of the alloy being aluminum. 
   
     
     
         4 . The method of  claim 3 , wherein the aluminum-scandium alloy includes about 0.2 wt % scandium as the at least one alloying element. 
     
     
         5 . The method of  claim 1 , wherein the pressure is applied to the molten casting material during and after the molten casting material is introduced into the mold and until the material solidifies. 
     
     
         6 . The method of  claim 1 , wherein the scandium precipitates are nanometer-sized precipitates randomly distributed throughout the turbocharger component. 
     
     
         7 . The method of  claim 1 , wherein the scandium precipitates are nanometer-sized precipitates evenly distributed throughout the turbocharger component. 
     
     
         8 . The method of  claim 1 , wherein a pressure of between 10 and 100 MPa is applied to the molten casting material by the movable portion of the ram. 
     
     
         9 . The method of  claim 1 , wherein the aging temperature is between 200° C. and 400° C. 
     
     
         10 . The method of  claim 1 , wherein the mold is pre-heated to 200° C. before introducing the molten casting material into the mold cavity. 
     
     
         11 . The method of  claim 1 , wherein the scandium precipitates are formed by aging the casting material at 300° C. for about 2 hours. 
     
     
         12 . The method of  claim 1 , wherein a coolant is pumped through coolant passages of the coolant member in directions both perpendicular to and parallel to the top of the mold. 
     
     
         13 . The method of  claim 1 , wherein the turbocharger component is a compressor wheel. 
     
     
         14 . A method of casting a turbocharger component for an internal combustion engine, the method comprising:
 heating an aluminum-scandium alloy to form a molten casting material including up to about 5 wt % scandium that is fully dissolved in the molten casting material;   introducing the molten casting material into a cavity of a mold from a bottom of the mold toward a top of the mold;   solidifying the molten casting material by cooling the casting material as it comes into contact with a cooling member positioned on the top of the mold, wherein a coolant is pumped through coolant passages formed in the cooling member in order to cool the casting material at a cooling rate such that the solidifying preserves at least 70% of an original amount of the scandium in the aluminum-scandium alloy in solid solution in the casting material; and   removing the solidified casting material from the mold.   
     
     
         15 . The method of  claim 14 , wherein the cooling rate is between about 5° C. per second and 200° C. per second. 
     
     
         16 . The method of  claim 14 , wherein the aluminum-scandium alloy comprises:
 1 to 4 wt % copper;   0 to 3 wt % magnesium;   0 to 7 wt % zinc;   0 to 2 wt % nickel;   0 to 2 wt % iron; and at least one of the following alloying elements:
 up to about 2 wt % scandium; 
 0 to 2 wt % zirconium; and 
 0 to 1 wt % titanium, with the balance of the alloy being aluminum. 
   
     
     
         17 . The method of  claim 16 , wherein the aluminum-scandium alloy includes about 0.2 wt % scandium as the at least one alloying element. 
     
     
         18 . The method of  claim 14 , wherein the scandium precipitates are nanometer-sized precipitates randomly distributed throughout the turbocharger component. 
     
     
         19 . A method of casting a component, the method comprising:
 heating an aluminum alloy to form a molten casting material including up to about 5 wt % of an alloying element that is fully dissolved in the molten casting material;   introducing the molten casting material into a cavity of a mold from a bottom of the mold toward a top of the mold;   solidifying the molten casting material by cooling the casting material as it comes into contact with a cooling member positioned on the top of the mold, wherein a coolant is pumped through coolant passages formed in the cooling member in order to cool the casting material at a cooling rate such that the solidifying preserves at least 70% of an original amount of the alloying element in the aluminum alloy in solid solution in the casting material;   removing the solidified casting material from the mold; and   forming precipitates of the alloying element within the casting material by aging the casting material at an aging temperature.   
     
     
         20 . The method of  claim 19 , wherein the cooling rate is between about 5° C. per second and 200° C. per second.