Patent ID: 9068252
Filing Date: 2015-06-30
Classification: C22C,C22F

Abstract:
1. A method of increasing the durability of at least one of a cylinder head and an engine block by improving a mechanical property of a permanent mold heat treatable aluminum alloy comprising: providing the heat treatable aluminum alloy in molten form to a cast in permanent mold defined in a shape of the at least one of the cylinder head and the engine block wherein the alloy is not subjected to high pressure die casting; heat treating the aluminum alloy at a solution treatment temperature for a first period of time; heating the heat treated aluminum alloy to a temperature about 5° C. to about 30° C. above the solution treatment temperature; cooling the heated aluminum alloy in air; pre-aging the cooled aluminum alloy at a temperature in a range of about room temperature to about 100° C.; and performing subsequent steps of aging after preaging to improve tensile strength of the at least one of the cylinder head and the engine block by aging the pre-aged aluminum alloy by two-step aging at an aging temperature above the pre-aging temperature and then at a second aging temperature higher than the aging temperature, wherein the pre-aging and the aging steps are each at least an hour; and wherein the temperature changes following pre-aging are either in steps, in a continuous manner, or a combination thereof.