<span style="mso-ansi-language: BG;">Study of the Microstructure of Non-Standardized Alternative Piston Aluminum-Silicon Alloys After Various Modifications: Influence of Modifying Treatments on the Microstructure and Properties

The structure, properties and use of complex-alloyed hypereutectic aluminum-silicon alloys are reviewed. The emphasis of the study is placed on the control of the morphology of the primary separated silicon by treatment with various modifiers. The effects of various modifying elements on the shape and distribution of silicon are reviewed. The experimental work related to the simultaneous modification of primary silicon and that in the composition of the eutectic is reviewed. The conclusion is that favorable effects can be obtained by using complex modifying treatment with the help of modifiers of the first and second kind. The studied non-standardized piston alloys AlSi18Cu3CrMn and AlSi18Cu5Mg after casting are subjected to T6 heat treatment in order to increase the mechanical performance, aiming to use the maximum potential of the alloying elements. After heat treatment, the shape and distribution of the primary separated silicon and the silicon crystals in the composition of the eutectic were studied by microstructural analysis and their microhardness was determined.