Analysis of structural properties of aluminium skeleton castings regarding the crystallization kinetics

Purpose: The aim of this research was the definition of technological parameters influence and modification treatment on structural properties of closed skeleton castings. Approach obtained maximal refinement of structure and minimal structure diversification. Design/methodology/approach: Skeleton castings were manufactured in acccordance to elaborated production technology. The subject of the research was the microstructural analysis of non - monolithic castings. Analisys of metallographic specimens and quantitative analysis of silicon crystals and secondary dentrite-arm spacing analysis of solution α were performed. Studies were executed for typical regions of skeleton castings. The regions were diversified regarding the cooling rate. Findings: Technological condictions and modification treatment were determined on advantageous structural properties (the great homogeneity and the greatest degree of fineness of microstructure). On basis of the reserach autors confirmed that in applied condictions of solidifiaction advantageous structur of AlSi11 alloy was obtained. Research limitations/implications: In the future autors will pursue to define influence of different modifiers (than antimony) on structural properties of skeleton castings. The modifiers are generally applied to refinement the structure of eutectic aluminium alloys. The aim of future resarch will be also to define optimum technological parameters which generate the best structural properties. Practical implications: This article shows method of structure design of AlSi11 alloys skeleton castings. This is essential with regard on usable properties of skeleton castings in future technical applications. Originality/value: Value of article is the elaborated manufacturing technology of skeleton castings and two methods of structure design of non - monolithic constructions with complicated geometry. The first method depended on elaborated parameters technological guidelines and advantageous technological condictions which enables to obtain the best structural properties. The second method depended on use of modifier which improve castability of AlSi11 alloys and enables to obtaine good filling of core channels of skeleton castings with more homogeneous structure.