High strength aluminum alloys for low pressure die casting and gravity casting

Abstract

Methods of casting lightweight, high-strength aluminum cast structural components are provided wherein the casting is accomplished by low-pressure die casting or gravity casting. The aluminum cast structural component is preferably composed of an aluminum-based alloy comprising silicon at ≥about 4 to ≥about 7 wt. %; iron at ≥about 0.15 wt. %; manganese at ≥about 0.5 wt. %; chromium at ≥about 0.15 to ≥about 0.5 wt. %; magnesium at ≥about 0.8 wt. %; zinc at ≥about 0.01 wt. %; titanium at ≥about 0.05 to ≥about 0.15 wt. %; phosphorus at ≥about 0.003 wt. %; strontium at ≥about 0.015 wt. % and a balance of aluminum.

What is claimed is: 
     
         1 . A method of forming a lightweight, high-strength cast structural component comprising:
 casting an aluminum-based alloy comprising silicon at greater than or equal to about 4 to less than or equal to about 7 wt. %; iron at less than or equal to about 0.15 wt. %; manganese at less than or equal to about 0.5 wt. %; chromium at greater than or equal to about 0.15 to less than or equal to about 0.5 wt. %; magnesium at less than or equal to about 0.8 wt. %; zinc at less than or equal to about 0.01 wt. %; titanium at greater than or equal to about 0.05 to less than or equal to about 0.15 wt. %; phosphorus at less than or equal to about 0.003 wt. %; strontium at less than or equal to about 0.015 wt. %; and a balance of aluminum to form the lightweight, high-strength cast structural component.   
     
     
         2 . The method of  claim 1 , wherein the lightweight, high-strength cast structural component has a yield strength of greater than or equal to about 270 MPa. 
     
     
         3 . The method of  claim 1 , wherein the lightweight, high-strength cast structural component has an elongation of greater than or equal to about 7%. 
     
     
         4 . The method of  claim 1 , wherein the lightweight, high-strength cast structural component has an elongation of greater than or equal to about 9%. 
     
     
         5 . The method of  claim 1 , wherein the casting is a low-pressure die casting process. 
     
     
         6 . The method of  claim 1 , wherein the casting is a gravity casting process. 
     
     
         7 . The method of  claim 5 , further comprising T6 heat treating the lightweight, high-strength cast structural component after the casting. 
     
     
         8 . The method of  claim 5 , wherein the magnesium is present in an amount of greater than or equal to about 0.1 to less than or equal to about 0.6 wt. % and the strontium is present in an amount of greater than or equal to about 0.01 to less than or equal to about 0.015 wt. %. 
     
     
         9 . The method of  claim 6 , wherein the magnesium is present in an amount of greater than or equal to about 0.1 to less than or equal to about 0.5 wt. %; the phosphorus is present at less than or equal to about 0.001 wt. %; and the strontium is present in an amount of less than or equal to about 0.005 wt. %. 
     
     
         10 . A method of forming a lightweight, high-strength cast structural component comprising:
 gravity casting an aluminum-based alloy comprising silicon at greater than or equal to about 4 to less than or equal to about 7 wt. %; iron at less than or equal to about 0.15 wt. %; manganese at less than or equal to about 0.5 wt. %; chromium at greater than or equal to about 0.15 to less than or equal to about 0.5 wt. %; magnesium at less than or equal to about 0.8 wt. %; zinc at less than or equal to about 0.01 wt. %; titanium at greater than or equal to about 0.05 to less than or equal to about 0.15 wt. %; phosphorus at less than or equal to about 0.003 wt. %; strontium at less than or equal to about 0.015 wt. %; and a balance of aluminum.   
     
     
         11 . The method of  claim 10 , wherein the lightweight, high-strength cast structural component has a yield strength of greater than or equal to about 270 MPa. 
     
     
         12 . The method of  claim 10 , wherein the lightweight, high-strength cast structural component has an elongation of greater than or equal to about 7%. 
     
     
         13 . The method of  claim 10 , further comprising T6 heat treating the lightweight, high-strength cast structural component after the casting. 
     
     
         14 . The method of  claim 10 , wherein the magnesium is present in an amount of greater than or equal to about 0.1 to less than or equal to about 0.5 wt. %; the strontium is present in an amount of less than or equal to about 0.005 wt. %; and the phosphorus is present in an amount of less than or equal to about 0.001 wt. %. 
     
     
         15 . A method of forming a lightweight, high-strength cast structural component comprising:
 low-pressure die casting an aluminum-based alloy comprising silicon at greater than or equal to about 4 to less than or equal to about 7 wt. %; iron at less than or equal to about 0.15 wt. %; manganese at less than or equal to about 0.5 wt. %; chromium at greater than or equal to about 0.15 to less than or equal to about 0.35 wt. %; magnesium at less than or equal to about 0.8 wt. %; zinc at less than or equal to about 0.01 wt. %; titanium at greater than or equal to about 0.05 to less than or equal to about 0.15 wt. %; phosphorus at less than or equal to about 0.003 wt. %; strontium at less than or equal to about 0.015 wt. %; and a balance of aluminum to form the lightweight, high-strength cast structural component.   
     
     
         16 . The method of  claim 15 , wherein the lightweight, high-strength cast structural component has a yield strength of greater than or equal to about 270 MPa. 
     
     
         17 . The method of  claim 15 , wherein the lightweight, high-strength cast structural component has an elongation of greater than or equal to about 7%. 
     
     
         18 . The method of  claim 15 , wherein the lightweight, high-strength cast structural component has an elongation of greater than or equal to about 9%. 
     
     
         19 . The method of  claim 15 , further comprising T6 heat treating the lightweight, high-strength cast structural component after the casting. 
     
     
         20 . The method of  claim 15 , wherein the magnesium is present in an amount of greater than or equal to about 0.1 to less than or equal to about 0.6 wt. and the strontium is present in an amount of greater than or equal to about 0. 01 to less than or equal to about 0.015 wt. %.