Ultra-High Strength Aluminum Alloy Castings

A novel sand casting process, which includes solidification under elevated hydrostatic pressure, was used to successfully cast a high-strength Al-Zn-Mg-Cu-Sc alloy into sections with the thicknesses varying from 0.25 to 2.5 inches. The yield strength of 490-510 MPa, ultimate tensile strength of 600-625 MPa, and elongation of 8.0-12% were achieved in 0.25 to 1.25 inch thick sections after T6 temper. Both strengths and elongation rapidly decreased with a further increase in the casting thicknesses. Optimization of the casting, heat treatment and hot isostatic pressing process are currently in-progress aiming at achieving similar properties in thicker sections.  Castings made from this alloy can replace aluminum fabrications and hog-outs in industrial, automotive, aerospace and military applications.  ² UES, Inc. on the Air Force Contract No. FA8650-04-D-5233.