Coordinated control of multi-region solidification in complex-shaped die-cast wheels via cooling adjustment strategies to minimize defects and enhance performance

Abstract

Cooling parameter adjustment is essential to minimize defect formation in die-cast components. However, such adjustments induce regional differences in aluminum solidification behavior, potentially improving quality in certain areas while causing degradation in adjacent regions. This study innovatively investigates the evolution of defects, microstructure, and mechanical properties with varying cooling parameters across multiple regions in low-pressure die-cast (LPDC) A356 wheels. Experimental results reveal that the cooling parameter exerts a pronounced impact on defect generation in the thin-walled rim and spoke regions. LPDC wheels exhibit opposing trends in defects and mechanical properties between the rim/spoke and outer flange when subjected to identical cooling parameter modifications. As the cooling condition changes from process 2 to process 3, the elongation of the rim and the spoke decrease by 8.0 % and 5.4 %, respectively, while the UTS decreases by 43 MPa and 27 MPa, respectively, due to the increased formation of defects. In contrast, the outer flange exhibits improvements, with elongation and UTS increasing by 4.5 % and 7 MPa, respectively, owing to microstructural refinement under long cooling duration. The same trend occurs in the transition from process 4 to process 5. Additionally, mechanical property data indicate that cooling parameter adjustment effectively homogenizes the mechanical properties in LPDC wheels. Moreover, P2 not only achieves balanced mechanical properties across all regions but also reduces the consumption of the cooling medium. These findings provide valuable engineering insights for developing cooling strategies to achieve multi-regional performance control in complex-shaped die-cast components.