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1
Content available Influence of Rare Earth Sm Addition on Microstructure and Tensile Properties of Al-Si-Cu 319 Alloy
Patel D. N., Sutaria Mayur P.
Archives of Foundry Engineering
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2023
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Vol. 23, iss. 1
25--33
EN
In the present investigation, the influence of addition of the rare earth element samarium (Sm) in different concentrations (0, 0.1, 0.3, 0.5, 0.7 and 0.9wt.%) on the microstructure and tensile properties of the Al-Si-Cu 319 alloy have been evaluated. Microstructural constituents such as SDAS of α-Al and characteristics of eutectic silicon particles were observed by optical microscopy. It was concluded from the findings that Sm addition reduces the size of secondary dendrite arm spacings (SDAS) and altered the morphology of the eutectic silicon particles from needle-like to lamellar and smaller segments. The tensile properties of the Al-Si-Cu 319 alloy improved with the concentration of Sm. It was found that the highest tensile properties were obtained at 0.7wt.% addition of Sm, i.e., 55.5% higher than unmodified 319 alloy. With the further addition of the Sm above 0.7wt.%, it does not improve the tensile properties of the alloy. This can be attributed to the precipitation of the brittle and needle like quaternary Sm-rich intermetallic compounds observed through Scanning electron microscopy.
2
Content available Effect of Maximum Piston Velocity on Internal Homogeneity of AlSi9Cu3(Fe) Alloy Processed by High-Pressure Die Casting
Matejka Marek, Bolibruchowá Dana, Podprocká R.
Archives of Foundry Engineering
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2022
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Vol. 22, iss. 4
34--40
EN
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.
3
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.
4
Content available Thermal-Derivative Analysis and Precipitation Hardening of the Hypoeutectic Al-Si-Cu Alloys
Smolarczyk P. E., Krupiński M.
Archives of Foundry Engineering
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2019
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iss. 1
41--46
EN
The research focused on the influence of the solution temperature on the structure of precipitation hardening multi-component hypoeutectic aluminium alloys. The AlSi8Cu3 and AlSi6Cu4 alloys were used in the study and were subjected to a thermal-derivative analysis. The chemical composition and crystallization of phases and eutectics shift the characteristic points and the corresponding temperatures to other values, which affect to, for instance, the solution temperature. The alloys were supersaturated at 475°C (according to the determined temperature (TSol) and 505°C for 1.5 hours. Aging was performed at 180°C for 5 hours. The Rockwell hardness measurement, metallographic analysis of alloys by means of light microscopy as well as chemical and phase analysis using scanning electron microscopy and X-ray crystallography were carried out on alloys. The use of computer image analysis enabled the determination of the amount of the current Al2Cu phase in the alloys before and after heat treatment.
5
Content available Influence of Remelting AlSi9Cu3 Alloy with Higher Iron Content on Mechanical Properties
Matejka M., Bolibruchova D.
Archives of Foundry Engineering
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2018
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Vol. 18, iss. 3
25--30
EN
The paper deals with influence of multiple remelting on AlSi9Cu3 alloy with higher iron content on chosen mechanical properties. Multiple remelting may in various ways influence mechanical, foundry properties, gas saturation, shrinkage cavity, fluidity etc. of alloy. Higher presence of iron in Al-Si cast alloys is common problem mainly in secondary (recycled) aluminium alloys. 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. Iron in the used alloy was increased to about 1.4 wt. %, so that the influence of increased iron content can be investigated. In the paper, the effect of multiple remelting is evaluated with respect to the resulting mechanical properties in cast state, after the heat treatment (T5) and after natural aging. From the obtained results it can be concluded that the multiple remelting leads to change of chemical composition and affect the mechanical properties.
6
Content available Experimental and Simulation Tests on the Impact of the Conditions of Casting Solidification from AlSi9Cu3 Alloy on their Structure and Mechanical Properties
Hajkowski J., Ignaszak Z.
Archives of Foundry Engineering
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2018
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Vol. 18, iss. 1
167--175
EN
The impact of casting conditions on microstructure a and mechanical properties was described, especially for cast products from AlSi9Cu3 alloy. Particular attention was paid to the parameters of dendritic structure: DAS 1 and DAS 2. Selected mechanical properties (by static tension test) of test castings made using basic technologies of casting: GSC - gravity sand casting, GDC - gravity die-casting and HPDC - high-pressure die-casting, are presented for cast-on test bars and cast separately. Casts were made of the same alloy AlSi9Cu3. Fractures and the zone near the fracture (after static tension test) was subjected to VT - visual tests, PT - penetration tests and metallographic tests. The condition of porosity (fracture zone) was also assessed. The analysis of virtual results was performed using the NovaFlow & Solid system together with the database and they were compared to experimental tests. This way of validation was applied in order to assess the correlation between the local rate of cooling and the size of DAS for GSC, GDC and HPDC technologies. Finally, the correlation between the parameters of structure and mechanical properties with regard to the impact of porosity was signalized.
7
Content available Effect of Remelting on Microstructure of the AlSi9Cu3 Alloy with Higher Iron Content
Matejka M., Bolibruchova D.
Archives of Foundry Engineering
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2018
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Vol. 18, iss. 4
25--30
EN
Secondary or multiple remelted alloys are common materials used in foundries. For secondary (recycled) Al-Si-Cu alloys, the major problem is the increased iron presence. Iron is the most common impurity and with presence of other elements in alloy creates the intermetallic compounds, which may negatively affect the structure. The paper deals with effect of multiple remelting on the microstructure of the AlS9iCu3 alloy with increased iron content to about 1.4 wt. %. The evaluation of the microstructure is focused on the morphology of iron-base intermetallic phases in caste state, after the heat treatment (T5) and after natural aging. The occurrence of the sludge phases was also observed. From the obtained results can be concluded that the multiple remelting leads to change of chemical composition, changes in the final microstructure and also increases sludge phases formation. The use of heat treatment T5 led to a positive change of microstructure, while the effect of natural aging is beneficial only to the 3rd remelting.
8
Content available Effects Of T6 Heat Treatment With Double Solution Treatment On Microstructure, Hardness And Corrosion Resistance Of Cast Al-Si-Cu Alloy
Wiengmoon A., Sukchot P., Tareelap N., Pearce J. T. H., Chairuangsri T.
Archives of Metallurgy and Materials
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2015
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Vol. 60, iss. 2A
881--886
EN
Effects of T6 heat treatment with double solution treatment on microstructure, hardness and corrosion resistance of a cast A319 (Al-4.93wt%Si-3.47wt%Cu) alloy were investigated. The T6 heat treatment comprised of the first solution treatment at 500±5°C for 8 h, the second solution treatment in the temperature range of 510 to 530±5°C for 2 h followed by water quenching (80°C), and artificial aging at 170°C for 24 h followed by water quenching (80°C). Microstructure of the alloy was studied by optical microscopy and electron microscopy, Rockwell hardness was measured, and corrosion resistance in 0.1 M NaCl aqueous solution was determined by a potentiodynamic technique. The results revealed that the T6 heat treatment with double solution treatment led to an improvement in corrosion resistance and comparable macrohardness as compared to those obtained from the case of single solution treatment. The second solution treatment at 520°C is the optimum leading to relatively low corrosion current density without substantial drawbacks on breakdown potential or the width of passive range.
PL
W pracy badano wpływ obróbki termicznej T6 połączonej z podwójnym przesycaniem na mikrostrukturę, twardość oraz odporność na korozję stopu A316 (Al-4,93Si-3,47Cu w % wag.) otrzymanego metodą odlewania. Obróbkę termiczną T6 przeprowadzono w następujący sposób: w pierwszej kolejności stop poddano przesycaniu w temperaturze 500±5°C przez 8 godzin, a następnie w zakresie temperatur od 510 do 530±5°C przez 2 godziny, hartowanie wodą (80°C) oraz sztuczne starzenie w 170°C przez 24 godziny i ponowne hartowanie wodą (80°C). Mikrostrukturę stopu badano metodami mikroskopii optycznej i mikroskopii elektronowej. Pomiar twardości stopu wykonano metodą Rockwella. Odporność stopu na korozję w roztworze wodnym 0.1 M NaCl wyznaczono metodą potencjodynamiczną. Otrzymane wyniki wykazały, że obróbka termiczna T6 z podwójnym przesycaniem prowadzi do poprawy makrotwardości oraz odporności materiału na korozję w porównaniu do stopu poddanego pojedynczemu przesycaniu. Stwierdzono także, iż drugie przesycanie w temperaturze 520°C jest optymalne i prowadzi do stosunkowo niskiej gęstości prądu korozyjnego bez znaczących odchyleń potencjału rozkładowego lub szerokości zakresu pasywnego.
9
Content available The Microstructure of AlSi9Cu3 Alloy after Different Stages of Liquid Metal Preparation
Poloczek Ł., Dybowski B., Łuszczak M., Kiełbus A.
Archives of Foundry Engineering
|
2015
|
Vol. 15, iss. 1 spec.
89--92
EN
Aluminium alloys are one of the most important casting alloys. Among them, the Al-Si alloys comprise perhaps the most important group – about 80% of the aluminium casts are made of them. These materials are characterized by a very good technological properties, good corrosion resistance and tribological properties. Their main disadvantage is, however, presence of the massive, brittle silicon crystals. They significantly affect alloys mechanical properties. Liquid metal treatment is essential for modification of Al-Si eutectic structure. The following work presents results of the research on the microstructure of the AlSi9Cu3 alloy after different stages of liquid metal preparation. Three casting processes have been conducted, chemical composition of the material in each case was in agreement with EN 1706 specification. During each casting process, three specimens were gravity cast: first, made from pure ingots; second, after the scrap addition and third one after the liquid metal treatment. Qualitative and quantitative evaluation of the microstructure was done on each specimen. Specimens cast from pure ingots are characterized by a refined Al-Si eutectic microstructure. After scrap addition, the silicon crystals became morphology of the massive platelets. What is more, intermetallic phases observed within the structure posses different morphologies after different stages of liquid metal preparation. After scrap addition, increased gas porosity was observed. Liquid metal treatment reduced slightly the formation of gas pores.
10
Content available remote Rola składu chemicznego podczas obróbki cieplnej stopów Al-Si-Cu
Kaczorowski M., Krzyńska A.
Krzepnięcie Metali i Stopów
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1998
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nr 36
111--120
PL
Nieustanne dążenie do zmniejszenia masy konstrukcji powoduje wzrost wymagań stawianych materiałom konstrukcyjnym. Dotyczy to również tworzyw odlewniczych, zarówno z grupy stopów Fe jak i Al. Wśród tych ostatnich najpowszechniej stosowanymi są stopy Al-Si często zawierające dodatek Cu i Mg, które umożliwiają ich obróbkę cieplną zwaną umacnianiem wydzieleniowym. W warunkach przemysłowych parametry obróbki cieplnej, takie jak temperatura i czas, są ustalone dla danego stopu pod kątem uzyskania założonych właściwości mechanicznych. Z drugiej strony wiadomo, że każda norma dopuszcza mniejsze lub większe odchylenie od składu chemicznego. [...]
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