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Study of Susceptibility to Tearing of AlSi5Cu2Mg Alloy with Addition of Zr and Ti

Matejka Marek, Bolibruchová Dana, Kantoríková Elena

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 1

107--114

EN

The current trend of continuous improvement of various components constantly pushes the development of new materials forward. The basic goal of research into new and better materials is to improve their properties compared to the original material. One of the essential properties of the newly developed aluminum alloys is their resistance to the formation of tearing. Tears appear during the solidification of the casting and break the integrity due to tension arising while cooling. Several factors influence the susceptibility to tearing, but they can be minimized and reduce the chance of their occurrence. As part of the experiment, the AlSi5Cu2Mg alloy was evaluated in four material variants, without additives (in the reference state), with the addition of transition elements Zr, Ti and their combination Zr + Ti. Susceptibility to the formation of tears was assessed using a qualitative method supplemented by microscopic analysis of the tear profile and determination of the dendritic coherence temperature. The evaluation shows that the addition of Zr increased the susceptibility to tear formation. On the contrary, the addition of Ti had a positive effect and reduced the susceptibility to the formation of tears. The effect of the addition of Zr and Ti in the AlSi5Cu2Mg alloy showed a similar values as without the addition of alloys (reference condition). Microstructural analysis of the tear profile pointed to the negative influence of phases rich in Zr. The subsequent evaluation of the dendritic coherence temperature of individual AlSi5Cu2Mg alloys did not show a correlation with the results of a quantitative evaluation of susceptibility to tears.

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Tests of Mechanical and Thermal Deformation of Moulding Sands Produced in Various Technologies

Grabarczyk Aleksandra, Major-Gabryś Katarzyna, Jakubski Jarosław, Dobosz Stanisław Marian, Bolibruchová Dana, Pastirčák Richard

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 3

933--937

EN

Casting industry has been enriched with the processes of mechanization and automation in production. They offer both better working standards, faster and more accurate production, but also have begun to generate new opportunities for new foundry defects. This work discusses the disadvantages of processes that can occur, to a limited extend, in the technologies associated with mould assembly and during the initial stages of pouring. These defects will be described in detail in the further part of the paper and are mainly related to the quality of foundry cores, therefore the discussion of these issues will mainly concern core moulding sands. Four different types of moulding mixtures were used in the research, representing the most popular chemically bonded moulding sands used in foundry practise. The main focus of this article is the analysis of the influence of the binder type on mechanical and thermal deformation in moulding sands.

3

Microstructure, Mechanical Properties and Corrosion Behavior of Zr-Containing AlSi5Cu2Mg Alloy

Bolibruchová Dana, Širanec Lukáš, Kajánek Daniel, Chalupová Mária

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 2

749--756

EN

The aim of this paper was to analyze the impact of varying zirconium addition on selected properties of AlSi5Cu2Mg alloy. The results of this research showed that zirconium addition in the range of 0.05 to 0.20 wt. % caused a decrease in ultimate tensile strength and yield strength of the experimental alloys after T7 heat treatment, probably due to the formation of primary Al3Zr intermetallic phases. These phases were observed as an individual plates or as a formation of two crossed plate-like phases. Potentiodynamic polarization tests in 3.5% NaCl solution revealed that addition of Zr had a positive effect on thermodynamic corrosion stability of the AlSi5Cu2Mg alloy due to shift of the corrosion potential to a more positive values for all as-cast samples. Addition of Zr in the as-cast alloys improved corrosion kinetics by lowering of corrosion current density.

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Fabrication of Surface Layer Enriched with Zinc on AlSi17 Aluminium Cast Alloy by Hot-Dip Galvanizing

Bucki Tomasz, Bolibruchová Dana

Journal of Casting & Materials Engineering

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2019

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Vol. 3, no. 4

67--70

EN

The paper deals with the fabrication of the surface layer enriched with Zn on AlSi17 aluminium alloy to modify the microstructure and surface properties of the alloy. The continuous surface layer was fabricated on the AlSi17 substrate by the hot-dip galvanizing of AlSi17 for 15min in a Zn bath heated to 450°C. The thickness of the layer was about 100 μm. The layer was characterised by a multi-component microstructure containing the regions of a solid solution of Al in Zn and dendrites of a eutectoid composed of a solid solution of Al in Zn and a solid solution of Zn in Al. In the layer, fine particles of Si with a regular shape were distributed. The results indicated that these Si particles formed by the action of Zn on the eutectic Si precipitations in the AlSi17 substrate. In the microstructure, large primary Si crystals and multi-phase precipitations, originating from the substrate, were also observed. The surface layer had much higher microhardness than the AlSi17 substrate. The results showed that hot-dip galvanizing can be used to modify the microstructure and properties of the surface layer of AlSi17. The study indicates the possibility of conducting further research on the fabrication of joints between AlSi17 and other metallic materials using a Zn interlayer fabricated by hot-dip galvanizing.