The mechanical properties of high-pressure die-casted parts are directly influenced by their microstructure. This article aims to evaluate the effect of the fast-shot speed on the structural component and overall microstructure for two geometrically different castings. The material used during experimental works is commonly known as the AlSi9Cu3(Fe) alloy. For experimental purposes, numerical simulations, microstructural and EDS analysis, the DAS index, length of eutectic Si plates and more were implemented. The simulations have shown the possibility of air entrapment in the filling chamber. Oxides, and consequently microporosity, were localized, which led to the selection of critical points of the casts for further observation and evaluation. With the use of the optical/scanning microscope and microhardness evaluation, the fast-shot speed value of 3.6 m.s−1 was selected as the most advantageous.

An oxide layer is formed on the surface of a molten aluminium alloy when it is exposed to the surrounding atmosphere. The oxide layer on the surface of the melt is not harmful. The problem occurs when it is entrained into the melt volume and solidifies in the casting. The paper deals with the formation of the oxide layer, its types and the formation of a double oxide layers.

The aim of the presented paper was to carry out a review of the internal structure of alloys used for high pressure die casting (HPDC) and to experimentally perform a structural analysis of AlSi9Cu3(Fe) alloy. Several castings with varying casting parameter – maximum plunger speed vmax were cast. In pre-selected critical locations, a change in porosity was observed with the change of the speed, and the casting samples with vmax = 2 and 3 m∙s-1 showed the lowest porosity. The effect of vmax was also observed on the shape and size of the structural components, where at higher vmax the eutectic Si grew in length and decreased in thickness. EDS analysis determined found intermetallic phases to be α-Al(Fe,Mn,Cr)Si in the shape of a rhombic dodecahedron with sizes as small as 2 µm and Al2Cu occurring in both modifications – oblong grains and globular ternary eutectic.

A number of technological parameters influence the mechanical properties of a high pressure die casting. The aim of the presented paper was to perform microstructural analysis of AlSi9Cu3(Fe) alloy casting fabricated with high-pressure die casting (HPDC) technology. Several castings with varying casting parameter – maximum plunger speed vmax were cast. In pre-selected critical spots, the effect of vmax was observed on the shape and size of the structural components, where at lower vmax the eutectic Si shortened in length and thickened. EDS analysis determined found intermetallic phases to be α-Al(Fe,Mn,Cr)Si in the shape of a rhombic dodecahedron with sizes as small as 2 µm and Al2Cu being present in both modifications – oblong grains and globular ternary eutectic. There was no significant change in microhardness of α(Al) phase found, that would be caused by the varying vmax