Effects of die-casting defects on the blister formation in high-pressure die-casting aluminum structural components

Abstract

The following work aims to present the casting defects effect in AlSi10MnMg alloy structural components on the blister’s possibility. Structural components must exhibit high mechanical properties, specifically high ductility. That requires the heat treatment process. However, the component’s exposure to high temperatures can cause blistering on the surface, which is unacceptable in the final product.For microstructure studies, the samples were cut from regions close to the gating system (hot areas) and those away from it (cold areas). For comparison, the paper studied castings in the as-cast state and after T7 heat treatment. The results suggest that the blistering process begins at casting defects, which create microstructural discontinuities. If gases are present in a discontinuity, they expand during solution treatment, forming surface blisters. The largest blisters form on cold flakes, mainly in casting areas near the gating system.However, smaller blisters form on porosity - both gas and shrinkage. The last casting defects that act as blistering sites are cold drops, cold shots, and thin oxide films occurring mainly in areas away from the gating system.