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Abstract

Manganese is an effective element used for the modification of needle intermetallic phases in Al-Si alloy. These particles seriously

degrade mechanical characteristics of the alloy and promote the formation of porosity. By adding manganese the particles are being

excluded in more compact shape of “Chinese script” or skeletal form, which are less initiative to cracks as Al5FeSi phase. In the present

article, AlSi7Mg0.3 aluminium foundry alloy with several manganese content were studied. The alloy was controlled pollution for achieve

higher iron content (about 0.7 wt. % Fe). The manganese were added in amount of 0.2 wt. %, 0.6 wt. %, 1.0 wt. % and 1.4 wt. %. The

influence of the alloying element on the process of crystallization of intermetallic phases were compared to microstructural observations.

The results indicate that increasing manganese content (> 0.2 wt. % Mn) lead to increase the temperature of solidification iron rich phase

(TAl5FeSi) and reduction this particles. The temperature of nucleation Al-Si eutectic increase with higher manganese content also. At

adding 1.4 wt. % Mn grain refinement and skeleton particles were observed.

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Authors and Affiliations

D. Bolibruchová
R. Podprocká
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Abstract

Iron is presented as an impurity in Al-Si alloys and occurs in the form of the β-Al5FeSi phase formations. The presence of iron and other elements in the alloy causes the formation of large intermetallic phases. Due to the high brittleness of this phase, it reduces the mechanical properties and increases the porosity. Manganese is used to inhibit the formation of this detrimental phase. It changes the morphology of the phase to polyhedral crystals, skeletal formations, or Chinese script. The present article deals with the influence of various amounts of manganese (0.1; 0.2; 0.4; 0.6 wt. %) on the formation of iron-based intermetallic phases in the AlSi7Mg0.3 alloy with different levels of iron content (0.4; 0.8, 1.2 wt. %). The increase of iron content in each alloy caused the creation of more intermetallic compounds and this effect has been more significant with higher concentrations of manganese. In alloys where the amount of 1.2 wt. % iron is present, the shape of eutectic silicon grain changes from angular to short needle type.
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Authors and Affiliations

D. Bolibruchová
R. Podprocká
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Abstract

This article deals with the effect of manganese that is the most applied element to eliminate the negative effect of iron in the investigated alloy AlSi7Mg0.3. In this time are several methods that are used for elimination harmful effect of iron. The most used method is elimination by applying the additive elements, so-called iron correctors. The influence of manganese on the morphology of excluded ironbased intermetallic phases was analysed at various iron contents (0.4; 0.8 and 1.2 wt. %). The effect of manganese was assessed in additions of 0.1; 0.2; 0.4 and 0.6 wt. % Mn. The morphology of iron intermetallic phases was assessed using electron microscopy (SEM) and EDX analysis. The increase of iron content in investigated alloys caused the formation of more intermetallic phases and this effect has been more significant with higher concentrations of manganese. The measurements carried out also showed that alloys with the same Mn/Fe ratio can manifest different structures and characteristics of excluded iron-based intermetallic phases, which might, at the same time, be related to different resulting mechanical properties.

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Authors and Affiliations

D. Bolibruchova
R. Podprocká
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Abstract

In Al-Si alloy the iron is the most common impurity and with presence of other elements in alloy creates the intermetallic compounds,

which decreases mechanical properties and increases of porosity. The cause of the negative effect of intermetallic particles on the

mechanical properties is that it is more easily break off the tension load as the aluminium matrix or small particles of silicon. By adding

suitable alloying elements, also known as iron correctors, is possible to reduce this harmful effect.

In the article is evaluated influence of manganese on microstructure with performed EDX analysis selected intermetallic phases and tensile

test and measurement of length of Al5FeSi phase. For realization experiments was used AlSi7Mg0.3 alloy with increased iron content.

Manganese was added in the amount 0.3 wt. %, 0.6 wt. %, 0.8 wt.% and 1,2 wt. %. From performed measurements it has been concluded,

that increased amount of manganese, i.e. Mn/Fe ratio, does not have significant influence on mechanical properties AlSi7Mg0.3 alloy in

the melted state.

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Authors and Affiliations

D. Bolibruchová
R. Podprocká
M. Chalupová
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Abstract

The paper deals with the influence of manganese in AlSi7Mg0.3 alloy with higher iron content. Main aim is to eliminate harmful effect of intermetallic – iron based phases. Manganese in an alloy having an iron content of about 0.7 wt. % was graded at levels from 0.3 to 1.4 wt. %. In the paper, the effect of manganese is evaluated with respect to the resulting mechanical properties, also after the heat treatment (T6). Morphology of the excluded intermetallic phases and the character of the crystallisation of the alloy was also evaluated. From the obtained results it can be concluded that the increasing level of manganese in the alloy leads to an increase in the temperature of the β-Al5FeSi phase formation and therefore its elimination. Reducing the amount of β-Al5FeSi phase in the structure results in an improvement of the mechanical properties (observed at levels of 0.3 to 0.8 wt. % Mn). The highest addition of Mn (1.4 wt.%) leads to a decrease in the temperature corresponding to the formation of eutectic silicon, which has a positive influence on the structure, but at the same time the negative sludge particles were also present

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Authors and Affiliations

D. Bolibruchová
R. Podprocká
R. Pastirčák
K. Major-Gabryś
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Abstract

High-pressure die casting results in a high quality surface and good mechanical properties of castings. Under the effect of pressure, integral and solid castings are achieved without a large number of foundry defects. The correct and proper setting of technological parameters plays a very important role in minimizing casting defects. The aim of the presented article is to determine the optimum maximum piston velocity for a casting in the high-pressure casting process with two height variants, depending on their internal quality. It is because the internal quality of particular castings is important in terms of proper functionality in operations where the biggest problem is the porosity of the casting. The main cause of porosity formation is the decreasing solubility of gases (most often hydrogen) during the melt solidification. Solubility represents the maximum amount of gas that can dissolve in a metal under equilibrium conditions of temperature and pressure. Macroporosity and microporosity were determined from the sections of the surfaces in the determined zones of the castings. Here, the results was that the macroporosity decreased with increasing piston velocity. Ideal microstructure was evaluated at a piston velocity of 3 m/s for both types of castings. On the other hand, the increase in tube size has shown that velocities of 3 m/s and higher, the tube is more prone to macroporosity formation. The highest hardness was achieved at the piston velocity of 2 m/s at both tube lengths.
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Authors and Affiliations

M. Matejka
1
ORCID: ORCID
D. Bolibruchová
1
ORCID: ORCID
R. Podprocká
2

  1. University of Zilina, Faculty of Mechanical Engineering, Department of Technological Engineering, Slovak Republic
  2. Rosenberg-Slovakia s.r.o., Slovak Republic
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Abstract

The technology of high-pressure die-casting (HPDC) of aluminum alloys is one of the most used and most economical technology for mass production of castings. High-pressure die-casting technology is characterized by the production of complex, thin-walled and dimensionally accurate castings. An important role is placed on the effective reduction of costs in the production process, wherein the combination with the technology of high-pressure die-casting is the possibility of recycling using returnable material. The experimental part of the paper focuses on the analysis of a gradual increase of the returnable material amount in combination with a commercial purity alloy for the production of high-pressure die-castings. The returnable material consisted of the so-called foundry waste (defective castings, venting and gating systems, etc.). The first step of the experimental castings evaluation consisted of numerical simulations, performed to determine the points of the casting, where porosity occurs. In the next step, the evaluation of areal porosity and microstructural analysis was performed on experimental castings with different amounts of returnable material in the batch. The evaluation of the area porosity showed only a small effect of the increased amount of the returnable material in the batch, where the worst results were obtained by the casting of the alloy with 90% but also with 55% of the returnable material in the batch. The microstructure analysis showed that the increase in returnable material in the batch was visibly manifested only by a change in the morphology of the eutectic Si.
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Bibliography

[1] Ragan, E. (2007). Die casting of metals. Prešov, Slovakia. (in Slovak).
[2] Eperješi, Ľ., Malik, J., Eperješi Š. & Fecko D. (2013) Influence of returning material on porosity of die castings. Manufacturing Technology. 13(1), 36-39. DOI: 10.21062/ujep/x.2013/a/1213-2489/MT/13/1/36.
[3] Gaustad, G., Olivetti, E. A. & Kirchain, R. (2012). Improving aluminum recycling: A survey of sorting and impurity removal technologies. Resources Conservation and Recycling. 58, 79-87.
[4] Matejka, M., Bolibruchová, D. & Kuriš, M. (2021). Crystallization of the structural components of multiple remelted AlSi9Cu3 alloy. Archives of Foundry Engineering. 21(2), 41-45. DOI: 10.24425/afe.2021.136096.
[5] Bruna, M., Remišová, A. & Sládek, A. (2019). Effect of filter thickness on reoxidation and mechanical properties of aluminium alloy AlSi7Mg0.3. Archives of Metallurgy and Materials. 3, 1100-1106. DOI: 10.24425/amm.2019.129500.
[6] Bryksi Stunova, B. & Bryksi, V. (2016). Analysis of defects in castings cast by rheocasting method SEED. Archives of Foundry Engineering. 16(3), 15-18. DOI: 10.1515/afe-2016-0041.
[7] Podprocká, R. & Bolibruchová, D. (2017). Iron intermetallic phases in the alloy based on Al-Si-Mg by applying manganese. Archives of Foundry Engineering. 17(3), 217-221. DOI: 10.24425/afe.2020.133321.
[8] Martinec, D., Pastircak, R. & Kantorikova, E. (2020). Using of technology semisolid squeeze casting by different initial states of material. Archives of Foundry Engineering. 20(1), 117-121. DOI: 10.24425/afe.2020.131292.
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Authors and Affiliations

M. Matejka
1
ORCID: ORCID
D. Bolibruchová
1
ORCID: ORCID
R. Podprocká
2

  1. University of Zilina, Faculty of Mechanical Engineering, Department of Technological Engineering, Univerzitna 1, 010 26 Zilina, Slovak Republic
  2. Rosenberg-Slovakia s.r.o., Kováčska 38, 044 25 Medzev, Slovak Republic

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