A heat treatment method for the direct quench of aluminum alloy castings is presented. An aluminum alloy casting can be heated to the solutionizing temperature. The temperature can be maintained for a period of time sufficient to dissolve the hardening elements into the aluminum solid solution and affect any morphological changes to non-soluble phases, such as speriodization of the eutectic silicon phase. After solutionizing, the aluminum alloy casting can be quenched. The aluminum alloy casting can be rapidly cooled from the solutionizing temperature directly to the aging temperature, eliminating the room temperature hold of a conventional process. Thereby, the process can reduce process steps and equipment, can improve throughput, and can eliminate some waste heat. Further, the process can reduce residual stress and can provide a potential to form new precipitates. Direct quench can also be used with the sequential aging of aluminum casting alloys.