Optimization of quench history of aluminum parts for superior mechanical properties

Cooling of an age-hardenable aluminum alloy after the high temperature forming process influences the metallurgical structure and, hence, the mechanical properties of the part. An intelligent spray quenching system is proposed which selects the optimal spray nozzle configuration based on part geometry and composition such that the quenched part attains superior mechanical properties. The present study demonstrates a method for maximizing the magnitude and uniformity of hardness (and yield strength) and qualitatively minimizing residual stresses within the quenched part by manipulation of spray intensity and hydrodynamic characteristics. Furthermore, the quenching of a complex-shaped alloy with multiple, partially overlapping sprays was successfully modeled using spray heat transfer correlations as boundary conditions within a finite element program. The results of this study facilitate the eventual incorporation of optimization techniques such that the nozzle configuration for a given part can be selected prior to quenching, thus achieving superior part quality with minimal costs.