Aluminum-silicon cast alloys, as those considered in this study (Al-7%Si and Al-7%Si-0.3%Mg alloys), are widely used to manufacture technical cast products, e.g. in the automotive industry. The mechanical properties of the castings depend on the eutectic microstructure which, in turn, depends on the chemical composition and manufacturing processes. A transition from a coarse eutectic structure to a finer one is called modification. The modification can be induced, for instance, by increasing the solidification cooling rate, by adding strontium and/or by increasing the alloy purity. The assessment of the modification relies usually on visual comparison, thus being ambiguous. This work suggests innovative tools to evaluate the microstructure based on quantitative image data and it develops an objective method to assess the modification. To ensure the representativeness of this method, it has been developed in collaboration with thirteen experts from different research institutions and companies. The assessment tools are applied to study the quantitative correlation between process settings, microstructures and casting properties, which are of major importance for the research and development of the studied alloys.
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