Complex Structure Modification and Improvement of Properties of Aluminium Casting Alloys with Various Silicon Content

The possibility of using complex structure modification for aluminium casting alloys’ mechanical properties improvement was studied. The fluxes widely used in the industry are mainly intended for the modification of a single structural component of Al–Si alloys, which does not allow unifying of the modification process in a production environment. Thus, a new modifying flux that has a complex effect on the structure of Al–Si alloys has been developed. It consists of the following components: TiO2, containing a primary α-Al grain size modifier; BaF2 containing a eutectic silicon modifier; KF used to transform titanium and barium into the melt. The effect of the complex titanium dioxide-based modifier on the macro-, microstructure and the mechanical properties of industrial aluminium–silicon casting alloys containing 5%, 6%, 9%, 11% and 17% Si by weight was studied. It was found that the tensile strength (σB) of Al–Si alloys exceeds the similar characteristics for the alloys modified using the standard sodium-containing flux to 32%, and the relative elongation (δ) increases to 54%. The alloys’ mechanical properties improvement was shown to be the result of the flux component’s complex effect on the macro- and microstructure. The effect includes the simultaneous reduction in secondary dendritic arm spacing due to titanium, the refinement and decreasing size of silicon particles in the eutectic with barium and potassium, and the modifying of the primary silicon. The reliability of the studies was confirmed using up-to-date test systems, a significant amount of experimental data and the repeatability of the results for a large number of samples in the identical initial state.

Influence of excess silicon phase on the thermal expansion behaviours of Al-Si binary casting alloys

Al-Si casting alloys are the most commonly used materials for piston alloys. The coefficient of thermal expansion is the key property of a piston material for improving the overall performance and service life of an engine. In the present study, the relationship between the morphology of the excess silicon phase and the coefficient of thermal expansion of Al-Si binary casting alloys was discussed. Optical and scanning electron microscopy were utilized to observe the morphology of the excess silicon phase in the Al-Si binary casting alloys before and after solution aging treatment. The results showed that the morphology of the excess silicon phase significantly influenced the coefficient of thermal expansion of the Al-Si binary casting alloys. After solution aging treatment, the coefficient of thermal expansion of the Al-Si binary casting alloys increased due to the rounding and granulating of the excess silicon phase precipitated during the casting process and decreased due to the precipitation of the finely dispersed Si phase in the α-Al matrix. The change in the coefficient of thermal expansion depended on which of the two kinds of morphological transformation of the excess silicon phase is dominant.

Fullerenes and prospects of their use in foundry and metallurgical production

The article is devoted to a special nanostructured form of carbon – fullerenes; the discovery of which became one of the most important events in the field of physics in the 80s of the last century. The article discusses the issues of obtaining and using fullerenes and other nanostructured materials; including hybrid ones; in foundry and metallurgical production: for modifying casting alloys; binders and auxiliary molding materials; for obtaining ceramic and hybrid nanocomposites; and for other purposes. It also provides information on the creation and operation of the world’s leading research centers specializing in the synthesis and application of nanomaterials in metallurgy and foundry.

An IT System for the Remote Burden Optimization of Foundry Furnaces

The burden calculations for foundry furnaces are one of the most important steps in preparing the production of liquid casting alloys. These calculations, due to the usually large number of input materials and chemical elements, are realized by numerical methods. These methods are implemented in some spreadsheets, universal mathematical programs or in specialized programs for foundry engineering. The paper describes a computerized system for remote calculations of optimal burden. The technological, economic, and organizational features of implementing IT system have been presented, also taking into account its safety of use.