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1
Content available Mold Temperature and Its Effect on Selected Properties of Cast AlSi5Cu2Mg Alloy
Širanec L., Bolibruchová D., Chalupova M.
Archives of Foundry Engineering
|
2022
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Vol. 22, iss. 2
57--62
EN
The European Commission's ambitious plan to reduce CO2 emissions has a significant impact on the global automotive industry. Recent development of new diesel and petrol engines with direct injection is aimed at improving fuel efficiency while maintaining (or enhancing) engine performance. This naturally also increases the demands on the properties of the most stressed engine components (e.g., cylinder heads, engine blocks, pistons), which leads to the development of new materials. Presented work analysed the effect of different mold temperatures (60; 120; 180 °C) on mechanical, physical properties and microstructure of AlSi5Cu2Mg aluminium alloy. This alloy is currently being used for the production of cylinder head castings. The results showed that the changing mold temperature had an effect on mechanical properties (ultimate tensile strength and Young modulus values). SEM with EDX analysis of intermetallic phases revealed there were no size and morphology changes of Cu, Mg and Fe intermetallic phases when the mold temperature changed. No significant effect of different mold temperature on physical properties (thermal and electrical conductivity) and fracture mechanism occurred during experiment. Optimal combination of mechanical and physical properties of AlSi5Cu2Mg alloy was achieved using a permanent mold with temperature ranging from 120 to 180 °C.
2
Content available Study of the Properties of the AlSi9Cu3 Alloy Depending on the Ratio of Returnable Material in the Batch
Matejka M., Bolibruchová D., Chalupová M.
Archives of Metallurgy and Materials
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2021
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Vol. 66, iss. 1
15--23
EN
Recycling of aluminium returnable material through its reuse is now an essential component of the production of aluminium alloy castings. The main goal is to find a suitable ratio of the primary alloy and the returnable material in the batch, thus determining the right compromise between the price and the quality of the casting. Experimental alloys were evaluated by thermal analysis, combination of structural analytical techniques and selected mechanical properties. The alloys were also subjected to tearing susceptibility testing. The increase in the returnable material amount resulted in changes in the alloy properties at the first increase in volume to 20%. After exceeding the balanced ratio (50:50), there was considerable degradation of the microstructure, failure to achieve the minimum values of some mechanical properties required by the standard, and the alloy showed increased susceptibility to tearing.
3
Content available Effect of Ti on Selected Properties of AlSi7Mg0.3Cu0.5 Alloy with Constant Addition of Zr
Bolibruchová D., Kuriš M., Matejka M., Major-Gabryś K., Vicent M.
Archives of Metallurgy and Materials
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2021
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Vol. 66, iss. 1
65--72
EN
The article is focused on the synergic effect of constant content of Zr and higher content of Ti on mechanical properties Al-Si alloy. The Ti additions were in proportions of 0.1, 0.2 and 0.3 wt.% Ti. The casting process was carried out in ceramic molds, created for the investment casting technology. Half of the experimental samples were processed by precipitation curing T6. The measured results were compared with primary alloy AlSi7Mg0.3 and experimental alloy AlSi7Mg0.3Cu0.5Zr0.15. In variant with addition 0.1 wt. %, the tensile strength Rm increased by 1,5% but the elongation AM decreased to 40%. Variants with 0.2 and 0.3 wt. % addition of Ti achieved similar Rm but approximately 40% decrease in AM. However, it is interesting that yield strength Rp0.2 increased for all variants by approximately 14 to 20%. The results point out the possibility of developing a more sophisticated alloy for automotive industry.
4
Content available A Study of Microstructure and Porosity Formation in High-Pressure Die-Casting
Matejka Marek, Bolibruchová D., Podprocká R.
Archives of Foundry Engineering
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2021
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Vol. 21, iss. 4
127--130
EN
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.
5
Content available Effect of Zirconium on the Solidification Path and Structural Properties of Commercial AlSi10MgCu Alloys
Hajduch P., Djurdjevic M. B., Bolibruchová D., Simicevic Z.
Archives of Metallurgy and Materials
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2020
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Vol. 65, iss. 2
549--554
EN
Comprehensive understanding of the melt quality is of vital importance for foundry man. The effect of each particular element need to be properly analysed. Therefore, the aim of this paper was to analyse the impact of various content of zirconium on the solidification path and structural characteristics (SDAS, grain size, porosity) of as cast commercial AlSi10MgCu alloys. It has been found that addition of zirconium up to 0.24 wt.% reduce significantly the grains size (from 3.5 mm to 1.2 mm), SDAS (from 57.3 μm to 50.4 μm) and porosity (from 19% to 5%), leading to production of sound cast parts.
6
Content available The Influence of Moulding Sand Type on Mechanical and Thermal Deformation
Grabarczyk A., Major-Gabryś K., Dobosz S. M., Jakubski J., Bolibruchová D., Brůna M., Pastirčák R.
Archives of Metallurgy and Materials
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2019
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Vol. 64, iss. 1
347--351
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.
7
Content available Impact of Zirconium on the Structural and Mechanical Properties of Commercial AlSi10MgCu Alloys
Hajduch P., Djurdjevic M. B., Bolibruchová D., Simicevic Z.
Archives of Metallurgy and Materials
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2019
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Vol. 64, iss. 3
1107--1110
EN
The impact of small addition of zirconium in hypoeutectic commercial AlSi10MgCu alloys on their mechanical properties (hardness) in as cast and thermally treated conditions was investigated. Small addition of zirconium does not change significantly the as cast and heat-treated microstructure of investigated alloys except to reduce the SDAS and grain size of primary α-aluminium phases. Addition of zirconium up to 0.14 wt. percentage increases the hardness of investigated alloys in as cast conditions. The increase in the hardness of samples after various solid solution times can correlate very well with the formation of small needle like coherent Al3Zr particles.
8
Content available The Influence of Different Wall Thicknesses of the Casting in the Direct Squeeze Casting
Pastirčák R., Brůna M., Bolibruchová D.
Archives of Foundry Engineering
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2019
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iss. 1
19--24
EN
The paper deals with squeeze casting technology. For this research a direct squeeze casting method has been chosen. As an experimental material, the AlSi12 and AlSi7Mg0.3 alloys were used. The influence of process parameters variation (pouring temperature, mold temperature) on mechanical properties and structure will be observed. For the AlSi7Mg0.3 alloy, a pressure of 30 MPa was used and for the AlSi12 alloy 50 MPa. The thicknesses of the individual walls were selected based on the use of preferred numbers and series of preferred numbers (STN ISO 17) with the sequence of 3.15 mm, 4 mm, 5 mm, 6.3 mm and 8 mm. The width of each wall was 22 mm and length 100 mm. The mechanical properties (Rm, A5) for individual casting parameters and their individual areas of different thicknesses were evaluated. For the AlSi7Mg0.3 alloy, the percentage increase of the tensile strength was up to 37% and the elongation by 400% (at the 8 mm thickness of the casting). For the AlSi12 alloy, the strength increased from 8 to 20% and the tensile strength increased from 5 to 85%. The minimum thickness of the wall to influence the casting properties by pressure was set to 5 mm (based on the used casting parameters). Due to the effect of the pressure during crystallization, a considerable refinement and uniformity of the casting structure occured, also a reduction in the size of the eutectic silicate-eliminated needles was observed.
9
Content available The Role of Mn in Aluminium Alloys with a Higher Iron Content
Bolibruchová D., Podprocká R., Pastirčák R., Major-Gabryś K.
Archives of Metallurgy and Materials
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2018
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Vol. 63, iss. 4
1883--1888
EN
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.
10
Content available Influence of Casting Wall Thickness on Crystallisation Under Pressure
Pastirčák R., Ščury J., Brůna M., Bolibruchová D., Jakubski J.
Archives of Metallurgy and Materials
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2018
|
Vol. 63, iss. 4
1889--1893
EN
The paper deals with squeeze casting technology. For this research a direct squeeze casting method has been chosen. The influence of process parameters variation (casting temperature, mold temperature, pressure) on mechanical properties and structure will be observed. The thicknesses of the individual walls were selected based on the use of preferred numbers and series of preferred numbers (STN ISO 17) with the sequence of 3.15, 4.00, 5.00, 6.00 and 8.00 mm. The width of each wall was 22 mm with a length of 100 mm. As an experimental material was chosen the AlSi12 and AlSi7Mg0.3 alloys. The mechanical properties (UTS, E) for individual casting parameters and their individual areas of different thicknesses were evaluated. In the structure the influence of pressure on the change of the eutectic morphology, the change of the volume of eutectic and the primary alpha phase, the effect of the pressure on the more fine-grain and the regularization of the structure were evaluated.
11
Content available Effect of Strontium Inoculation on Hot Tearing in Aluminium Alloys
Bolibruchová D., Bruna M., Pastirčák R., Major-Gabryś K.
Archives of Metallurgy and Materials
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2018
|
Vol. 63, iss. 4
1837--1842
EN
Main aim of submitted work is evaluation and experimental verification of inoculation effect on Al alloys hot-tear sensitivity. Submitted work consists of two parts. The first part introduces the reader to the hot tearing in general and provides theoretical analysis of hot tearing phenomenon. The second part describes strontium effect on hot tearing susceptibility, and gives the results on hot tearing for various aluminium alloys. During the test, the effect of alloy chemical composition on hot tearing susceptibility was also analyzed. Two different Al-based alloys were examined. Conclusions deals with effect of strontium on hot tearing susceptibility and confirms that main objective was achieved.
12
Content available Effect of Manganese and Iron Content on Morphology of Iron Intermetallic Phases in AlSi7Mg0.3 Alloy
Podprocká R., Bolibruchová D.
Archives of Foundry Engineering
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2018
|
Vol. 18, iss. 2
95--99
EN
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.
13
Content available Affecting the Crystallization of Al-based alloys by Electromagnetic Field
Bolibruchová D., Brůna M.
Archives of Foundry Engineering
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2018
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Vol. 18, iss. 2
157--162
EN
This article deal with non-conventional methods to affect the crystallization of Al-alloys by the application of electromagnetic field. The application of electromagnetic field is not technically complicated, it does not require mechanical contact with the melt, and the scale of the crystallization influence is not dependent on the thickness of the casting. Two experimental materials were used: AlSi10MgMn and AlSi8Cu2Mn and two values of electromagnetic induction: B = 0.1 T a B = 0.2 T. The best results for alloy AlSi10MgMn were achieved by application of electromagnetic field with induction B = 0.2 T; during this experiment the best mechanical properties were achieved - the biggest increase of mechanical properties was recorded. The best results for alloy AlSi8Cu2Mn were achieved by combination of electromagnetic field with induction B = 0.1 T and modification by 0.05 wt. % Sr. In this case we don´t recommend to use electromagnetic field with induction B = 0.2 T; because of deposition of coarse grains and decreasing of mechanical properties.
14
Content available Utilisation of mould temperature change in eliminating the Al5FeSi phases in secondary AlSi7Mg0.3 alloy
Bolibruchová D., Richtárech L., Dobosz S. M., Major-Gabryś K.
Archives of Metallurgy and Materials
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2017
|
Vol. 62, iss. 1
339--344
EN
This article describes the impact of the metal mould temperature change in eliminating the adverse effect of iron in the AlSi7Mg0.3 alloy. The kind of phases based on iron to be formed in aluminium alloys is determined by the alloy chemical composition, the melt overheating temperature prior to casting, and the cooling rate during crystallisation. In the experiment, we used three various mould temperatures, and their impact on the possible change in the adverse Al5FeSi phase, excreted in a needle form to a more compact form of Chinese writing or skeleton units. The experimental part did not use melt overheat that would result in impairment of the melt, for example due to increased gassing of the melt, as well as in a greater load on the smelting unit, thus resulting in increased energy expenditure. We can conclude from the obtained results that the mould temperature change does not have an adequate effect in eliminating the adverse effect of iron in Al-Si-Mg alloys.
15
Content available Antimony Influence on Shape of Eutectic Silicium in Al-Si Based Alloys
Bolibruchová D., Brůna M.
Archives of Foundry Engineering
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2017
|
Vol. 17, iss. 4
31--34
EN
Liquid AI-Si alloys are usually given special treatments before they are cast to obtain finer or modified matrix and eutectic structures, leading to improved properties. For many years, sodium additions to hypoeutectic and eutectic AI-Si melts have been recognized as the most effective method of modifying the eutectic morphology, although most of the group IA or IIA elements have significant effects on the eutectic structure. Unfortunately, many of these approaches also have associated several founding difficulties, such as fading, forming dross in presence of certain alloying elements, reduced fluidity, etc. In recent years, antimony additions to AI-Si castings have attracted considerable attention as an alternative method of refining the eutectic structure. Such additions eliminate many of the difficulties listed above and provide permanent (i.e.,non-fading) refining ability. In this paper, the authors summarize work on antimony treatment of Al-Si based alloys.
16
Content available Influence of Nickel Addition on Properties of Secondary AlSi7Mg0.3 Alloy
Richtárech L., Bolibruchová D., Brůna M., Caiss J.
Archives of Foundry Engineering
|
2015
|
Vol. 15, iss. 2
95--98
EN
This paper deals with influence on segregation of iron based phases on the secondary alloy AlSi7Mg0.3 microstructure by nickel. Iron is the most common and harmful impurity in aluminum casting alloys and has long been associated with an increase of casting defects. In generally, iron is associated with the formation of Fe-rich intermetallic phases. It is impossible to remove iron from melt by standard operations. Some elements eliminates iron by changing iron intermetallic phase morphology, decreasing its extent and by improving alloy properties. Realization of experiments and results of analysis show new view on solubility of iron based phases during melt preparation with higher iron content and influence of nickel as iron corrector of iron based phases.
17
Content available Elimination of Iron Based Particles in Al-Si Alloy
Bolibruchová D., Richtárech L.
Archives of Foundry Engineering
|
2015
|
Vol. 15, iss. 1
9--12
EN
This paper deals with influence on segregation of iron based phases on the secondary alloy AlSi7Mg0.3 microstructure by chrome. Iron is the most common and harmful impurity in aluminum casting alloys and has long been associated with an increase of casting defects. In generally, iron is associated with the formation of Fe-rich phases. It is impossible to remove iron from melt by standard operations, but it is possible to eliminate its negative influence by addition some other elements that affect the segregation of intermetallics in less harmful type. Realization of experiments and results of analysis show new view on solubility of iron based phases during melt preparation with higher iron content and influence of chrome as iron corrector of iron based phases. By experimental work were used three different amounts of AlCr20 master alloy a three different temperature of chill mold. Our experimental work confirmed that chrome can be used as an iron corrector in Al-Si alloy, due to the change of intermetallic phases and shortening their length.
18
Content available Vanadium Influence on Iron Based Intermetallic Phases in AlSi6Cu4 Alloy
Bolibruchová D., Žihalová M.
Archives of Metallurgy and Materials
|
2014
|
Vol. 59, iss. 3
1029--1032
EN
Negative effect of iron in Al-Si alloys mostly refers with iron based intermetallic phases, especially Al5FeSi phases. These phases are present in platelet-like forms, which sharp edges are considered as main cracks initiators and also as contributors of porosity formation. In recent times, addition of some elements, for example Mn, Co, Cr, Ni, V, is used to reduce influence of iron. Influence of vanadium in aluminium AlSi6Cu4 alloy with intentionally increased iron content is presented in this article. Vanadium amount has been graduated and chemical composition of alloy has been analysed by spectral analysis. Vanadium influence on microstructural changes was evaluated by microstructural analysis and some of intermetallic particles were reviewed by EDX analysis.
PL
Negatywny wpływ żelaza w stopach Al-Si związany jest głównie z tworzeniem faz międzymetalicznych, szczególnie Al5FeSi. Fazy te występują w postaci płytkowej, których ostre krawędzie uważa się za główna przyczynę inicjacji pęknięć oraz zarodkowania porowatości. Obecnie w celu redukowania wpływu żelaza wprowadza się dodatek niektórych pierwiastków, np. Mn, Co, Cr, Ni, V. Wpracyprzedstawia się wpływ wanadu w stopie AlSi6Cu4 z celowo zwiększoną zawartością żelaza. W badaniach dodatek wanadu był stopniowany, a skład chemiczny określano w analizie spektralnej. Wpływ wanadu na zmiany strukturalne określono na drodze analizy mikrostruktury, natomiast cząstki faz międzymetalicznych opisano za pomocą analizy EDX.
19
Content available Elimination of Negative Effect of Fe in Secondary Alloys AlSi6Cu4 (En Ac 45 000, A 319) by Nickel
Bolibruchová D., Macko J., Brůna M.
Archives of Metallurgy and Materials
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2014
|
Vol. 59, iss. 2
717--721
EN
Submitted article deals with influence of iron based phases segregation by nickel, which is in literature known as iron based phases corrector. Iron is one of the most common impurities that can be found in Al-Si alloys. It is impossible to remove iron from melt by standard operations, but it is possible to eliminate iron negative effects by addition of other elements, that enables segregation of iron in form of intermetallics with less harmful effect. For melt treatment was selected an exact alloy with requested iron content - master alloy AlNi20. Influence of nickel was evaluated quantitatively by chemical analysis (solubility), thermal analysis and microstructure evaluation. Experimental results analysis shows a new view on solubility of iron based phases during melt preparation and treatment with higher iron content and also nickel effect as iron corrector of iron based phases. It can be concluded that nickel did not influenced iron based phases (β-phases), it does not change their type into more favorable form. As an initial impulse for starting this work was insufficient theoretical knowledge of usage secondary alloys Al-Si-Cu with higher iron content and its appropriate elimination in process of castings production for automotive industry. Increased iron content in alloys causes segregation of iron phases in various shapes and types during solidification, which subsequently affects quality, soundness and lifetime of castings. Because of increased demands for casting quality, final mechanical properties and effort to reduce costs, it is necessary to look for compromises in casting production from secondary alloys with occurrence of various impurities.
PL
Artykuł opisuje wpływ dodatku niklu| do stopów wtórnych Al-Si-Cu na segregację faz zawierających żelazo, które jest jednym z najpowszechniej występujących zanieczyszczeń w tych stopach. Powszechnie wiadomo, iż nie jest możliwe usunięcie żelaza z kąpieli metalowej, natomiast można ograniczać negatywny jego wpływ poprzez związanie żelaza w fazach między- metalicznych mniej szkodliwych niż fazy β Fe, np. w następstwie dodatku innych pierwiastków. W badaniach do obróbki kąpieli zastosowano zaprawę AlNi20 z dokładnie określoną zawartością żelaza. Oddziały wanie niklu na skład i morfologię faz żelazowych określano na drodze analizy chemicznej (badania rozpuszczalności), analizy termicznej i oceny struktury. Na podstawie wyników badań stwierdzono, iż w badanych stopach nikiel nie wywiera wpływu na zmianę składu fazy β Fe, nie zmienia również kształtu jej wydzieleń do postaci bardziej korzystnej z punktu widzenia wpływu na właściwości.
20
Content available Influence of Iron in AlSi10MgMn Alloy
Žihalová M., Bolibruchová D.
Archives of Foundry Engineering
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2014
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Vol. 14, iss. 4
109--112
EN
Presence of iron in Al-Si cast alloys is common problem mainly in secondary (recycled) aluminium alloys. Better understanding of iron influence in this kind of alloys can lead to reduction of final castings cost. Presented article deals with examination of detrimental iron effect in AlSi10MgMn cast alloy. Microstructural analysis and ultimate tensile strength testing were used to consider influence of iron to microstructure and mechanical properties of selected alloy.
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