Cast aluminum alloys for automotive applications by microstructure refinement using tsp treatment

Abstract

A method of casting an aluminum alloy is provided. The method includes casting a master aluminum alloy having a trisilanol phenyl polyhedral oligomeric silsesquioxanes (TSP) modifier into an ingot and adding the master aluminum alloy ingot into a molten base aluminum alloy to form a modified aluminum alloy. The modified aluminum alloy is heated for a period of time and then cast into a cast component. A variation of the method includes mixing a powdered aluminum alloy with a powdered TSP and pressing the mixture of powdered TSP and powdered aluminum alloy into a compacted preform prior to casting the master aluminum alloy. The compacted preform is melted during the step of casting the master aluminum alloy.

What is claimed is: 
     
         1 . A method of casting an aluminum alloy comprising:
 casting a master aluminum alloy having a trisilanol phenyl polyhedral oligomeric silsesquioxanes (TSP) modifier into an ingot;   adding the master aluminum alloy ingot into a molten base aluminum alloy to form a modified aluminum alloy;   heating the modified aluminum alloy for a period of time; and   casting the modified aluminum alloy into a cast component.   
     
     
         2 . The method according to  claim 1  further comprising, prior to casting the master aluminum alloy:
 mixing a powdered aluminum alloy with a powdered TSP; and 
 pressing the mixture of powdered TSP and powdered aluminum alloy into a compacted preform, 
 wherein the compacted preform is melted during the step of casting the master aluminum alloy. 
 
     
     
         3 . The method according to  claim 2 , wherein a plurality of compacted preforms are pressed and subsequently melted during the step of casting the master aluminum alloy. 
     
     
         4 . The method according to  claim 1 , wherein the modified aluminum alloy is degassed prior to casting. 
     
     
         5 . The method according to  claim 1 , wherein the master aluminum alloy is an aluminum-silicon (AlSi) based alloy. 
     
     
         6 . The cast component according to the method of  claim 5  comprising a microstructure having fibrous eutectic Si. 
     
     
         7 . The method according to  claim 1 , wherein the modified aluminum alloy is cast into a clay-graphite crucible. 
     
     
         8 . The method according to  claim 1 , wherein the modified aluminum alloy is continually heated for the period of time with a parts per million (ppm) loss of less than 10%. 
     
     
         9 . The method according to  claim 8 , wherein the modified aluminum alloy is continually heated at or above 700° C. for the period of time. 
     
     
         10 . The method according to  claim 9 , wherein the period of time is at least 1.5 hours. 
     
     
         11 . The method according to  claim 1 , wherein the modified aluminum alloy is Al-7.5Si having an increase in ductility of at least 15% above an Al-7.5Si alloy without TSP. 
     
     
         12 . The method according to  claim 1 , wherein the modified aluminum alloy is Al-7.5Si having an increase in ultimate tensile strength of at least 5% above an Al-7.5Si alloy without TSP. 
     
     
         13 . The method according to  claim 1 , wherein the modified aluminum alloy is continually heated at or above 700° C. and the period of time is greater than 72 hours. 
     
     
         14 . The method according to  claim 13 , wherein the modified aluminum alloy has a parts per million (ppm) loss of less than 10%. 
     
     
         15 . A method of casting an aluminum alloy comprising:
 mixing a powdered aluminum alloy with a powdered TSP;   pressing the mixture of powdered TSP and powdered aluminum alloy into a compacted preform;   casting a master aluminum alloy from the compacted preform and into an ingot;   adding the master aluminum alloy ingot throughout a molten base aluminum alloy to form a modified aluminum alloy; and   casting the modified aluminum alloy into an ingot.   
     
     
         16 . The method according to  claim 15 , wherein the modified aluminum alloy is degassed prior to casting. 
     
     
         17 . The method according to  claim 15 , wherein the master aluminum alloy is an aluminum-silicon (AlSi) alloy and the modified aluminum alloy comprises a microstructure having fibrous eutectic Si. 
     
     
         18 . The method according to  claim 15 , wherein the modified aluminum alloy has a parts per million (ppm) loss of less than 10% after being continually heated at or above 700° C. for a period of time greater than 1.5 hours. 
     
     
         19 . A method of casting an aluminum alloy comprising:
 casting a master aluminum alloy having a trisilanol phenyl polyhedral oligomeric silsesquioxanes (TSP) modifier into an ingot;   adding the master aluminum alloy ingot into a molten base aluminum alloy to form a modified aluminum alloy;   heating the modified aluminum alloy for a period of time; and   casting the modified aluminum alloy into an ingot,   wherein the modified aluminum alloy has a parts per million (ppm) loss of less than 10% after being continually heated at or above 700° C. during the period of time, and the period of time is greater than 1.5 hours.   
     
     
         20 . The method according to  claim 19  further comprising, prior to casting the master aluminum alloy:
 mixing a powdered aluminum alloy with a powdered TSP; and 
 pressing the mixture of powdered TSP and powdered aluminum alloy into a compacted preform, 
 wherein the compacted preform is melted during the step of casting the master aluminum alloy.