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Lantanowce: przegląd eutektycznych modyfikacji pod-eutektycznych stopów Al-Si. Część 1

Gursoy Ozen, Timelli Giulio

Przegląd Odlewnictwa

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2022

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Vol. 72, nr 5-6

256--261

PL

Modyfikowana struktura, podobna do włóknistej, znacznie poprawia finalne mechaniczne właściwości (głównie ciągliwość) stopów odlewniczych. Poza szeroko stosowanymi, komercyjnymi, eutektycznymi modyfikatorami, takimi jak Sr i Na, lantanowce wydają się być pozytywną alternatywą dla procesu modyfikacji eutektycznego Si w podeutektycznych stopach odlewniczych Al-Si. Wszystkie lantanowce mają podobne fizyczne i chemiczne właściwości takie jak gęstość, temperaturę topnienia i zjawiska zanikania, które zostały omówione i porównane w obecnym przeglądzie. One również mają promienie atomowe zbliżone do optymalnego promienia atomowego czynnika modyfikującego. Jednakże, mikrostrukturalne wydzielanie się eutektycznego Si jest ściśle związane z konkretnym pierwiastkiem i zawartością lantanowców, których obfitość, zasoby, wydobywanie, produkcja i sytuacja na rynku zostały wstępnie ocenione w tej pracy. Mechanizmy eutektycznej modyfikacji wzbudzane prze lantanowce nie są jeszcze dobrze poznane i wyjaśnione. Pozytywne i negatywne strony dodatków poszczególnych lantanowców celem chemicznej modyfikacji podeutektycznych stopów Al-Si, zostały w niniejszej pracy krytycznie omówione. Stosowanie lantanowców do eutektycznej modyfikacji Si w stopach Al-Si zostało przedyskutowane, zarówno biorąc pod uwagę efektywność jak ekonomikę procesu. Obecnie, wydaje się że aktualny koszt i efektywność lantanowców powodują, że jeszcze daleko do ich stosowania w przemyśle odlewniczym na dużą skalę.

EN

A modified fibrous-like eutectic structure strongly improves the final mechanical properties of Al-Si foundry alloys, especially ductility. Beside widely used commercial eutectic modifiers such as Sr and Na, lanthanides appear to be a possible alternative in the eutectic Si modification process for hypoeutectic Al-Si casting alloys. All lantha nides have similar physical and chemical properties, such as density, melting point, and fading phenomena, which have been compared in the present review. They also show atomic radii close to the optimal atomic radius for a modifying agent. However, the microstructural evolution of eutectic Si is strictly related to the specific element and content of lanthanides, whose abundance, reserve, mining, production and market situations have been preliminary evaluated in this paper. The eutectic modification mechanisms induced by lanthanides are not well-discussed and clarified yet. The advantages and disadvan tages of individual addition of lanthanides for chemical modification of hypoeutectic Al-Si alloys have been here critically reviewed. The use of lanthanides for eutectic Si modification in Al-Si alloys has been discussed from both effectiveness and economical point of views. Nowadays, the actual cost and their efficiency seem to make lanthanides still far to be used in foundry industry for commercial and large-scale applications.

2

Lantanowce: przegląd eutektycznych modyfikacji pod-eutektycznych stopów Al-Si. Część 2

Gursoy Ozen, Timelli Giulio

Przegląd Odlewnictwa

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2022

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Vol. 72, nr 9-10

494--500

PL

Zmodyfikowana - podobna do włóknistej - eutektyczna struktura znacznie ulepsza finalne mechaniczne właściwości (zwłaszcza ciągliwość) odlewniczych stopów Al-Si. Poza szeroko stosowanymi komercyjnymi modyfikatorami eutektyki, takimi jak Sr i Na, lantanowce okazują się możliwą alternatywą w procesie eutektycznej modyfikacji Si dla podeutektycznych stopów Al-Si. Wszystkie lantanowce mają podobne fizyczne i chemiczne właściwości, takie jak gęstość, temperatura topnienia, oraz zjawiska zanikania, które są porównywane w tym przeglądzie. Lantanowce również mają promienie atomowe bliskie optymalnemu promieniowi czynnika modyfikującego. Jednakże, mikrostrukturalne wydzielanie się eutektycznego Si jest ściśle związane z konkretnym pierwiastkiem i zawartością lantanowców, których obfitość, zasoby, wydobywanie, produkcja i sytuacja na rynkach zostały wstępnie omówione w tej pracy. Mechanizmy eutektycznej modyfikacji wzbudzane przez lantanowce nie są jeszcze ani dobrze przedyskutowane, ani wyjaśnione. Pozytywne i negatywne strony indywidualnych dodatków lantanowców celem chemicznej modyfikacji podeutektycznych stopów Al-Si zostały tu krytycznie omówione. Użycie lantanowców celem eutektycznej modyfikacji Si w stopach Al-Si, zostało przedyskutowane zarówno z punktu widzenia ekonomii, jak efektywności. Wydaje się, że obecnie - z uwagi na koszty i skuteczność - jeszcze daleko do tego żeby lantanowce zostały użyte w przemyśle odlewniczym i w komercyjnych zastosowaniach na dużą skalę.

EN

A modified fibrous-like eutectic structure strongly improves the final mechanical properties of Al-Si foundry alloys, especially ductility. Beside widely used commercial eutectic modifiers such as Sr and Na, lanthanides appear to be a possible alternative in the eutectic Si modification process for hypoeutectic Al-Si casting alloys. All lanthanides have similar physical and chemical properties, such as density, melting point, and fading phenomena, which have been compared in the present review. They also show atomic radii close to the optimal atomic radius for a modifying agent. However, the microstructural evolution of eutectic Si is strictly related to the specific element and content of lanthanides, whose abundance, reserve, mining, production and market situations have been preliminary evaluated in this paper. The eutectic modification mechanisms induced by lanthanides are not well-discussed and clarified yet. The advantages and disadvantages of individual addition of lanthanides for chemical modification of hypoeutectic Al-Si alloys have been here critically reviewed. The use of lanthanides for eutectic Si modification in Al-Si alloys has been discussed from both effectiveness and economical point of views. Nowadays, the actual cost and their efficiency seem to make lanthanides still far from being used in foundry industry for commercial and large-scale applications.

3

Effect of novel grain refiner and Ni alloying additions on microstructure and mechanical properties of Al-Si9.8-Cu3.4 HPDC castings – optimization using Multi Criteria Decision making approach

Apparao K. Ch., Bannaravuri Praveen Kumar, Pulisheru Kumar Swamy, Francis E. D., Sunny Kalakanda Alfred, Babu Rao Gadudasu, Daniel P. Freedon, Kumar Birru Anil

Materials Science Poland

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2022

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Vol. 40, No. 1

9--24

EN

Studies dealing with process improvement of aluminum alloys and their grain structure refinement are the current area of interest in casting companies and foundries, the aim being to enhance the properties of the base metal. In this study, the microstructural and mechanical properties of commercial Al-Si9.8-Cu3.4 alloy die castings influenced by different additions of Al-3.5FeNb-1.5C master alloy (viz. 0 wt.%, 0.1 wt.%, and 1.0 wt.%) as a new grain refiner and Al-6Ni master alloy (viz. 0 wt.%, 0.5 wt.%, and 5.0 wt.%) as an alloying element have been investigated. A multi-criteria decision-making approach for the improvement of the die casting process was performed using grey relational analysis (GRA) and TOPSIS analytical techniques. It was observed that the primary aluminum α-grains were significantly refined, particularly at the lower addition level 0.1 wt.% of Al-3.5FeNb-1.5C, and conversely, poor grain refining efficiency was observed at a higher addition level 1.0 wt.% of Al-3.5FeNb-1.5C. Due to the refinement by Al-3.5FeNb-1.5C grain refiner and the effect of Ni alloying element additions, the ultimate tensile strength (UTS) and hardness (Brinell and micro) of the Al-Si9.8-Cu3.4alloy are improved, particularly at 0.1 wt.% of Al-3.5FeNb-1.5C and 0.5 wt.% of Al-6Ni master alloys. Quantitatively, UTS, Brinell hardness, and microhardness values have been increased by 12.3%, 7.0%, and 20%, respectively.

4

Plasma Coatings on Aluminium-Silicon Alloy Surfaces

Długosz P., Garbacz-Klempka A., Piwońska J., Darłak P., Młynarczyk M.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 3

96--101

EN

Plasma oxidation, similarly to anodic oxidation (anodizing), are classified as electrochemical surface treatment of metals such as Al, Mg, Ti and their alloys. This type of treatment is used to make surface of castings, plastically processed products, shaped with incremental methods to suitable for certain requirements. The most important role of the micro plasma coating is to protect the metal surface against corrosion. It is well known that coating of aluminium alloys containing silicon using anodic oxidation causes significant difficulties. They are linked to the eutectic nature of this alloy and result in a lack of coverage in silicon-related areas. The coating structure in these areas is discontinuous. In order to eliminate this phenomenon, it is required to apply oxidation coatings using the PEO (Plasma Electrolytic Oxidation) method. It allows a consistent, crystalline coating to be formed. This study presents the mechanical properties of the coatings applied to Al-Si alloy using the PEO method. As part of the testing, the coating thickness, microhardness and scratch resistance were determined. On the basis of the results obtained, it was concluded that the thickness of the coatings complies with the requirements of conventional anodizing. Additionally, microhardness values exceeded the results obtained with standard methods.

5

Microstructural investigation and wear characteristics of Al-Si-Ti cast alloys

Subhi Akeel Dhahir, Khleif Ali Abbar, Abdul-Wahid Qasim Saad

Engineering Transactions

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2020

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Vol. 68, iss. 4

385--395

EN

Hypoeutectic Al-7Si alloys containing various titanium proportions (0.8–1.6%) were produced and analyzed in this work. The wear characteristics of Al-Si alloys were studied under the conditions of dry sliding at various applied loads. Optical microscope (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to depict the microstructure, worn surface and phases, respectively. Phases of -Al, eutectic and Ti9Al23 were recognized in the Al-Si-Ti alloys matrix. Considerable coarsening took place in -Al and eutectic silicon in a fully eutectic through solidification. The hardness was increased as the titanium proportion increased. Furthermore, significant changes were found in the wear rate depending on the titanium proportion added and load applied.

6

The effect of the modification by ultrafine silicon carbide powder on the structure and properties of the Al-Si alloy

Kovbasiuk T. M., Selivorstov V. Yu., Dotsenko Yu. V., Duriagina Z. A., Kulyk V. V., Kasai O. M., Voitovych V. V.

Archives of Materials Science and Engineering

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2020

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Vol. 101, nr 2

57--62

EN

Purpose: Determine the possibility of modifying aluminium alloys of the Al-Si system with an ultrafine SiC modifier with a particie size of 3-5 pm. Design/methodology/approach: Processing of the Al-Si alloy was carried out by introducing an ultrafine modifier in the amount of 0.1, 0.2, or 0.3 wt.%. Silicon carbide (SiC) with a particle size in the range of 3-5 pm was used as a modifier. To study the microstructure of the formed surface layers, a metallographic analysis was performed according to the standard method on a microscope MIKPOTEX® MMT-14C using TopView software. Microhardness studies of the samples were carried out on a Vickers microhardness tester NOVOTEST TC-MKV1. The microstructure of castings of the AlSi12 grade was studied at magnification from 100 to 400 times on the horizontal and vertical surfaces of the samples after etching with a 2% NaOH aqueous solution. Findings: Aluminium cast alloy of Al-Si system has been synthesized with the addition of 0.1, 0.2, and 0.3 wt.% ultrafine SiC modifier. It was found that the modification of the AlSi12 alloy by SiC particles of 3-5 pm in size led to an improvement of its microstructure due to the reduction of the volume fraction of micropores and primary Si crystals. It was shown that the AlSi12 aluminium alloy due to the modification by 0.2 wt.% SiC has the best micromechanical properties and macrostructure density. Research limitations/implications: The obtained research results are relevant for cast specimens of the indicated sizes and shapes. The studies did not take into account the influence of the scale factor of the castings. Practical implications: The developed modification technology was recommended for use in the conditions of the foundry "Dnipropetrovsk Aggregate Plant" (Dnipro, Ukraine). Originality/value: The technology of AlSi12 alloy modification of ultrafine SIC modifier with a particle size of 3-5 pm was used for the first time.

7

The Effect of Modifier on the Microstructure of the AlSi10CuNiMn Alloy

Cais Jaromir, Heinrich Jiri, Jirounkova Klara

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 2

13--18

EN

This paper deals with different types of modifiers and their effect on the microstructure of the Al-Si alloy. For the purposes of this research, strontium, antimony and calcium were used as the modifiers of the AlSi10CuNiMn alloy. Unmodified alloy was cast in order to be compared with the alloy modified by different modifiers in various concentrations. The results of this research were analysed via light and electron microscopy.

8

Effect of Trace Elements (Co, Cr) on the Microstructure and Physical Properties of Al-Si-Cu-Mg-Fe Extruded Alloy

Ahn S. S., Sharief P., Lee C. H., Son H. T., Kim Y. H., Kim Y. C., Hong S., Hong S. J.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 3

857--862

EN

Trace elements Co, Cr were added to investigate their influence on the microstructure and physical properties of Al-Si extruded alloy. The Co, Cr elements were randomly distributed in the matrix, forms intermetallic phase and their existence wereconfirmed by XRD, EDS and SEM analysis. With addition of trace elements, the microstructure was modified, Si particle size was reduced and the growth rate of β-(Al5 FeSi) phase limited. Compared to parent alloy, hardness and tensile strength were enhanced while the linear coefficient of thermal expansion (CTE) was significantly reduced by 42.4% and 16.05% with Co and Cr addition respectively. It is considered that the low CTE occurs with addition of Co was due to the formation of intermetallic compound having low coefficient of thermal expansion. The results suggested that Co acts as an effective element in improving the mechanical properties of Al-Si alloy.

9

Effect of increased temperature on dimensional and shape accuracy of castings produced from the EN AC-AlSi11 alloy by pressure die casting process

Jarco A.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 1

325--328

EN

The present work discusses results of increased temperature on shape-dimensional changes of a 110 type hose coupling, produced from EN AC-AlSi11 alloy with the use of pressure die casting technology. The castings were soaked for 3.5 h at temperatures 460°C, 475°C and 490°C. The verification of shape-dimensional accuracy of the elements after soaking treatment, in relation to raw casting, was carried out by comparing the 3D models received from 3D scanning. Soaking temperature of about 460°C-475°C results in no significant changes in the shapes and dimensions of the castings, or surface defects in the form of blisters, which can be seen at a temperature of 490°C.

10

Improvement of Al-Si Alloy Fatigue Strength by Means of Refining and Modification

Tupaj M., Orłowicz A. W., Trytek A., Mróz M.

Archives of Foundry Engineering

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2019

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iss. 4

61--66

EN

The paper presents results of a study concerning an AlSi7Mg alloy and the effect of subjecting the liquid metal to four different processes: conventional refining with hexachloroethane; the same refining followed by modification with titanium, boron, and sodium; refining by purging with argon carried out in parallel with modification with titanium and boron salts and strontium; and parallel refining with argon and modification with titanium, boron, and sodium salts. The effect of these four processes on compactness of the material, parameters of microstructure, and fatigue strength of AlSi7Mg alloy after heat treatment. It has been found that the highest compactness (the lowest porosity ratio value) and the most favorable values of the examined parameters of microstructure were demonstrated by the alloy obtained with the use of the process including parallel purging with argon and modification with salts of titanium, boron, and sodium. It has been found that in the fatigue cracking process observed in all the four variants of the liquid metal treatment, the crucial role in initiation of fatigue cracks was played by porosity. Application of the process consisting in refining by purging with argon parallel to modification with Ti, B, and Na salts allowed to refine the microstructure and reduce significantly porosity of the alloy extending thus the time of initiation and propagation of fatigue cracks. The ultimate effect consisted in a distinct increase of the fatigue limit value.

11

Multistage discretization and clustering in multivariable classification of the impact of alloying elements on properties of hypoeutectic silumin

Regulski Krzysztof, Wilk-Kołodziejczyk Dorota, Kluska-Nawarecka Stanisława, Szymczak Tomasz, Gumienny Grzegorz, Jaśkowiec Krzysztof

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 1

114--126

EN

The properties of hypoeutectic Al–Si alloy (silumin) with the addition of elements such as Cr, Mo, V and W are described. Changes in silumin microstructure under the impact of these elements result in a change of the mechanical properties. The research includes presentation of procedure for the acquisition of knowledge about these changes directly from experimental results using mixed data mining techniques. The procedure for analyzing small sets of experimental data for multistage, multivariate and multivariable models has been developed. Its use can greatly simplify such research in the future. An interesting achievement is the development of a voting procedure based on the results of classification trees and cluster analysis.

12

Influence CuAl10Fe3Mn2 Additive on Ultimate Tensile Strength and WEAR of Al-9%SiMg Alloy

Lipiński T.

Tribologia

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2018

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nr 3

83--89

EN

One of the most common castings applied in industrial production is aluminium-silicon alloy (ca. 9% Si with Mg). The Al-SiMg alloys have high corrosion resistance, high strength to weight ratio with modifications, very good castability, a low thermal-expansion coefficient, and relatively good wear resistance. These properties make it possible to widely apply the foundry Al-9% SiMg alloy to number of aviation, automotive, and others materials working on tribological applications. Similar to silumins, the aluminium bronze CuAl10Fe3Mn2 is characterized by good mechanical properties and wear and corrosion resistance. This paper presents the research on the treatment of Al-9%SiMg alloy with a composition of CuAl10Fe3Mn2 in different mass ranges. The experiments were conducted by a factor plan 23 for three independent variables. The main additions were strontium, Al-9%SiMg, aluminium bronze, as well as pure or melted with raw silumin. The effect of the tested additions on the microstructure and tensile strength of the Al-9%SiMg alloy was presented in figures. All analysed parameters (mechanical and tribological) of the hypo-eutectic Al-9%SiMg alloy with tested bronze additions are improved. Based on the analysis of the study results, it was found that the microstructure and tensile strength of the tested alloy are determined through the contents introduced of CuAl10Fe3Mn2 to the alloy.

PL

Jednym z najczęściej stosowanych w produkcji przemysłowej stopów odlewniczych jest stop aluminium--krzem (ok. 9% Si z dodatkiem Mg). Stopy Al-SiMg charakteryzują się wysoką odpornością na korozję, w stanie zmodyfikowanym wysokim stosunkiem wytrzymałości do wagi odlewu, bardzo dobrą lejnością, niskim współczynnikiem rozszerzalności cieplnej, względnie dobrą odpornością na zużycie. Te właściwości umożliwiają szerokie zastosowanie odlewniczego stopu Al-9% SiMg do wielu materiałów lotniczych, motoryzacyjnych i innych pracujących również w zastosowaniach tribologicznych. Podobnie jak w przypadku siluminu brąz aluminiowy CuAl10Fe3Mn2 charakteryzuje się dobrymi właściwościami mechanicznymi, zużyciem i odpornością na korozję. W artykule przedstawiono badania dotyczące obróbki stopu Al-9% SiMg składnikiem CuAl10Fe3Mn2 w różnych zakresach masowych. Eksperymenty przeprowadzono za pomocą planu czynnikowego 23 dla trzech niezależnych zmiennych. Głównym dodatkiem były: stront Al-9%SiMg, brąz aluminiowy, zarówno czysty, jak i stopiony z surowym siluminem. Wpływ badanych dodatków na mikrostrukturę i wytrzymałość na rozciąganie stopu Al-9% SiMg przedstawiono na rysunkach. Wszystkie analizowane parametry (mechaniczne i tribologiczne) stopu podeutektycznego Al-9% SiMg z badanym dodatkiem brązu zostały poprawione. Na podstawie analizy wyników badań stwierdzono, że mikrostruktura i właściwości mechaniczne badanego stopu są określone przez zawartość CuAl10Fe3Mn2 wprowadzoną do stopu.

13

Metallurgical Processing of Al-Si Alloys with Increased Iron Content Using Sodium, Strontium, and Tellurium

Pokusová M., Berta I., Murgašová M.

Journal of Casting & Materials Engineering

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2018

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Vol. 2, no. 1

9--13

EN

This paper presents the results of research focused on the processing of the hypoeutectic Al-Si alloy with an increased iron content of 1.75 wt.%. The physical-metallurgical method was used to eliminate the undesirable effect of the iron rich b-phase on the mechanical properties of the casting material using liquid metal modification by strontium, sodium, and tellurium. The chemical composition of an experimental material didn’t contain any elements for the solid-solution strengthening of a matrix; therefore, the presented results can document the capabilities of modifying the b-phase under a minimum influence on the properties of the basic Al-Si system.

14

Correlation of Hardness and Silicon Morphology for Al-Si-Sb Alloy

Uzun O., Yilmaz F., Emeksiz C., Ergen S., Kolemen U.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 1

467--472

EN

In this study, we have focused on the role of silicon morphology on the hardness of eutectic Al–12 wt.% Si–0.5 wt.% Sb alloy solidified at different cooling rates. The alloys were produced by using induction melting, arc-remelting and melt-spinning techniques. The cooling rates of the alloys were determined as 0.5, 60 and ~105°C.s-1 for induction-melted, arc-remelted and meltspun alloy. The experimental results show that as the cooling rate increased the coarse silicon phase was substantially refined and its morphology altered from sharp need-like to round shape. Two exothermic peaks, attributed to precipitation and coarsening of silicon from supersaturated α-Al, were observed in the DSC curve of MS alloy. Vicker’s hardness of melt-spun alloy was found two times higher than those of IMed and ARed alloys. The lowest hardness of induction-melted alloy was ascribed to the lamellar morphology of silicon, yielding decohesive rupture. This result was confirmed by finite element analyzing.

15

Evaluation of the Effect of the Cr, Mo, V and W Content in an Al-Si Alloy Used for Pressure Casting on its Proof Stress

Szymczak T., Szymszal J., Gumienny G.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 2

105--111

EN

The study presents the results of the application of a statistical analysis for the evaluation of the effect of high-melting additions introduced into a pressure cast Al-Si alloy on the obtained level of its proof stress Rp0.2. The base Al-Si alloy used for the tests was a typical alloy used for pressure casting grade EN AC-46000. The base alloy was enriched with high-melting additions, such as: Cr, Mo, V and W. The additions were introduced into the base Al-Si alloy in all the possible combinations. The content of the particular high-melting addition in the Al-Si alloy was within the scope of 0.05 to 0.50%. The investigations were performed on both the base alloy and alloy with the high-melting element additions. Within the implementation of the studies, the values of Rp0.2 were determined for all the considered chemical compositions of the Al-Si alloy. A database was created for the statistical analysis, containing the independent variables (chemical composition data) and dependent variables (examined Rp0.2 values). The performed statistical analysis aimed at determining whether the examined high-melting additions had a significant effect on the level of Rp0.2 of the Al-Si alloy as well as optimizing their contents in order to obtain the highest values of the Al-Si alloy's proof stress Rp0.2. The analyses showed that each considered high-melting addition introduced into the Al-Si alloy in a proper amount can cause an increase of the proof stress Rp0.2 of the alloy, and the optimal content of each examined high-melting addition in respect of the highest obtained value of Rp0.2 equals 0.05%.

16

Modifications ALSI7MG0.3 alloys trough CA, SR and SB

Cais Jaromír, Lysoňková Irena, Kraus Pavel

Advances in Science and Technology. Research Journal

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2018

|

Vol. 12, no 2

180--187

EN

This article deals with examing the effect of modifier on changes in microstructure of the alloy AlSi7Mg0.3. The content of the experiment was to examine the effect of addition of calcium, stroncium, and antimony to change the morphology of the eutectic silicon in the alloy type of Al-Si (namely AlSi7Mg0.3). Besides changes in the morphology of eutectic silicon was explored focused on character exlusion modifiers within microstructure of the modified alloy. Examination of the microstructure was realized by scanning electron microscopy and complemented by EDX analysis of the examined samples.

17

Wpływ wanadu na proces krystalizacji, mikrostrukturę i właściwości siluminu EN AC-46000

Szymczak T., Gumienny G., Pacyniak T.

Prace Instytutu Odlewnictwa

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2017

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Vol. 57, no. 3

187--199

PL

W niniejszej pracy przedstawiono wyniki badań siluminu z dodatkiem wanadu przeznaczonego do odlewania pod ciśnieniem. Jako stop wyjściowy zastosowano silumin podeutektyczny gatunku EN AC-46000. Do siluminu wyjściowego wprowadzano zaprawę AlV10 w ilości pozwalającej na uzyskanie zawartości wanadu w kolejno wytapianych siluminach po około 0,1; 0,2; 0,3; 0,4 i 0,5% wag. Badaniom poddano zarówno silumin wyjściowy, jak i siluminy zawierające wanad. Badania obejmowały analizę termiczną i derywacyjną (ATD) procesu krystalizacji, analizę metalograficzną mikrostruktury odlewów wykonanych w próbniku ATD i ciśnieniowych oraz określenie podstawowych właściwości mechanicznych siluminu odlewanego ciśnieniowo. Badania ATD wykazały wzrost temperatury początku krystalizacji siluminu oraz brak dodatkowych efektów cieplnych. Badania metalograficzne wykazały zmniejszenie średniej wielkości faz w mikrostrukturze stopu odlewanego do próbnika ATD. W siluminach zawierających 0,3; 0,4 i 0,5% wag. V zarówno płytkowe wydzielenia krzemu eutektycznego, jak i faz międzymetalicznych pochodzących z eutektyk charakteryzują się znacząco mniejszymi maksymalnymi wymiarami w porównaniu z siluminami o mniejszej zawartości V. W mikrostrukturze siluminów odlewanych pod ciśnieniem, które zawierają wanad powstają „nowe” fazy niewystępujące w siluminach niezawierających tego pierwiastka. Są to najprawdopodobniej fazy międzymetaliczne zawierające wanad. Wielkość wydzieleń tych faz rośnie wraz ze zwiększeniem zawartości wanadu w siluminie. Przeprowadzone badania podstawowych właściwości mechanicznych siluminów odlewanych pod ciśnieniem wykazały możliwość uzyskania większych wartości wytrzymałości na rozciąganie Rm, umownej granicy plastyczności Rp0,2 oraz twardości HB siluminów zawierających wanad w porównaniu z siluminami bez tego pierwiastka. Największe wartości: Rm = 248 MPa uzyskano w siluminie zawierającym około 0,3% wanadu; Rp0,2 = 113 MPa przy zawartości 0,1 i 0,2% oraz HB = 116 dla dodatku V około 0,2% wag. Względem siluminu bez dodatku V uzyskane wartości powodują podwyższenie Rm o 26%; Rp0,2 o 12% oraz HB o 7%.

EN

The paper presents the results of the study of Al-Si alloys with a vanadium addition used in pressure casting. The hypoeutectic Al-Si alloy grade EN AC-46000 was applied as the initial alloy. The master alloy AlV10 was introduced into the initial alloy in the amount making it possible to obtain the vanadium content in the consecutively melted Al-Si alloys of about 0.1; 0.2; 0.3; 0,4 and 0.5 wt. %. The tests were performed on both the initial Al-Si alloy and alloys containing vanadium. The investigations included a thermal and derivative (DTA) analysis of the crystallization process, a metallographic analysis of the microstructure of casts prepared in DTA tester and pressure casts, as well as the determination of the basic mechanical properties of the pressure cast Al-Si alloy. The DTA tests showed an increase in the temperature at the beginning of the Al-Si alloy crystallization and no additional thermal effects. The metallographic examinations demonstrated a decrease of the average phase size in the microstructure of the alloy cast in the DTA tester. In the Al-Si alloys containing 0.3; 0.4 and 0.5 wt. % V, both the lamellar precipitates of eutectic silicon and of the intermetallic phases originating in the eutectics were characterized by significantly lower maximal dimensions, compared to the Al-Si alloys with lower V contents. In the microstructure of the pressure cast Al-Si alloys, which contain vanadium, “new” phases may form, which did not occur in the Al-Si alloys without V. These are probably intermetallic phases containing vanadium. The size of these precipitates increases with the increase of the vanadium content in the Al-Si alloy. The performed tests of the basic mechanical properties of the pressure cast Al-Si alloys showed the possibility of obtaining higher values of tensile strength Rm, proof stress Rp0.2 and hardness HB of the Al-Si alloys containing vanadium, compared to the Al-Si alloys without this element. The highest values: Rm = 248 MPa were obtained in the Al-Si alloy containing about 0.3% vanadium; Rp0.2 = 113 MPa – with the content of 0.1, and 0.2% and HB = 116 for the V addition of about 0.2 wt. %. As regards the Al-Si alloy without a vanadium addition, the obtained values caused an increase of Rm by 26%; Rp0.2 by 12% and HB by 7%.

18

The mechanical properties of AlSi coatings made by PVD technology

Kucharska B., Wróbel-Knysak A.

Mechanik

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2017

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R. 90, nr 1

66--67

PL

Porównano mechaniczne właściwości (mikrotwardość i test rysy) powłok AlSi wykonanych metodą PVD magnetronowego rozpylania stopów o zawartości 7–20% Si. Większe stężenie Si zwiększało opór odkształcania powłok wyrażony głębokością rysy. Lepsze właściwości mechaniczne miały powłoki ze stopów modyfikowanych TiBAl.

EN

The mechanical properties (microhardness and scratch test) of AlSi coatings made by PVD magnetron sputtering method from alloys with 7-20%Si were compared. Higher concentration of Si increased deformation resistance of the coating, expressed by depth of scratch. Improved mechanical properties had coatings from alloys modified by TiBAl refiner.

19

Modeling of Eutectic Formation in Al-Si Alloy Using A Phase-Field Method

Ebrahimi Z.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 4

1969--1981

EN

We have utilized a phase-field model to investigate the evolution of eutectic silicon in Al-Si alloy. The interfacial fluctuations are included into a phase-field model of two-phase solidification, as stochastic noise terms and their dominant role in eutectic silicon formation is discussed. We have observed that silicon spherical particles nucleate on the foundation of primary aluminum phase and their nucleation continues on concentric rings, through the Al matrix. The nucleation of silicon particles is attributed to the inclusion of fluctuations into the phase-field equations. The simulation results have shown needle-like, fish-bone like and flakes of silicon phase by adjusting the noise coefficients to larger values. Moreover, the role of primary Al phase on nucleation of silicon particles in Al-Si alloy is elaborated. We have found that the addition of fluctuations plays the role of modifiers in our simulations and is essential for phase-field modeling of eutectic growth in Al-Si system. The simulated finger-like Al phases and spherical Si particles are very similar to those of experimental eutectic growth in modified Al-Si alloy.

20

The Influence of Laser Surface Remelting on the Microstructure of EN AC-48000 Cast Alloy

Piątkowski J., Grabowski A., Czerepak M.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 4

217--221

EN

Paper present a thermal analysis of laser heating and remelting of EN AC-48000 (EN AC-AlSi12CuNiMg) cast alloy used mainly for casting pistons of internal combustion engines. Laser optics were arranged such that the impingement spot size on the material was a circular with beam radius rb changes from 7 to 1500 μm. The laser surface remelting was performed under argon flow. The resulting temperature distribution, cooling rate distribution, temperature gradients and the depth of remelting are related to the laser power density and scanning velocity. The formation of microstructure during solidification after laser surface remelting of tested alloy was explained. Laser treatment of alloy tests were perform by changing the three parameters: the power of the laser beam, radius and crystallization rate. The laser surface remelting needs the selection such selection of the parameters, which leads to a significant disintegration of the structure. This method is able to increase surface hardness, for example in layered castings used for pistons in automotive engines.