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1

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

Application of Natural and Artificial Ageing on Multiply Remelted AlSi9Cu3 Alloy

Matejka M., Bolibruchova D.

Archives of Foundry Engineering

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2019

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iss. 2

60--66

EN

This article focuses on the study of the influence of remelting and subsequent natural and artificial ageing on the structure of recycled AlSi9Cu3 alloy with increased iron content. The assessed changes in eutectic silicon and iron-based intermetallic phases were carried out using optical and scanning electron microscopy. The degradation of the eutectic silicon morphology due to remelting occurred only at the highest numbers of remelting. The effect of remelting the investigated alloy, which is accompanied by a gradual increase in wt. % Fe, began to manifest significantly through a change in the length of the ferric phases after the fourth remelting. As expected, the artificial ageing process has proven to be more effective than natural ageing. It has led to a change in the eutectic silicon morphology and has been beneficial in reducing the lengths of adverse ferric phases. The use of alloys with higher numbers of remelting, or with greater “contamination”, for the manufacture of shape-challenging castings is possible when using a suitable method of eliminating the negative factors of the remelting process. The results of our investigation show a suitable method of the above elimination the application of heat treatment T5 – via artificial ageing.

3

Structural analysis of heat treated automotive cast alloy

Tillová E., Chalupová M., Hurtalová L., Bonek M., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 47, nr 1

19--25

EN

Purpose: The present study is conducted to investigate and to provide a better understanding of the heat treatment T4 (solution treatment at 505, 515 and 525°C, holding time 2, 4, 8,16 and 32 hours, then quenching in warm water in the range from 40°C and natural aging at room temperature during 24 hours) on the microstructure (morphology of eutectic Si, morphology of intermetallic Fe- and Cu-rich phases) and on mechanical properties (tensile strength and Brinell hardness) of recycled (secondary) AlSi9Cu3 cast alloy. Design/methodology/approach: Metallographic samples were selected from tensile specimens (after testing) and prepared by standard metallographic procedures (wet ground, polished with diamond pastes, finally polished with commercial fine silica slurry (STRUERS OP-U) and etched by Dix-Keller, HNO3 or H2SO4 (standard etching) or HCl (deep etching in order to reveal the three-dimensional morphology of phases). The microstructure was studied using an optical microscope Neophot 32 and SEM observation with EDX analysis using scanning electron microscope VEGA LMU II linked to the energy dispersive X-ray spectroscopy (EDX analyser Brucker Quantax). Hardness measurement was performed by a Brinell hardness tester with a load of 62.5 kp (1 kp = 9.807 N), 2.5 mm diameter ball and a dwell time of 15 s. Findings: The results indicate that increasing solution treatment temperature results in spheroidization of eutectic Si, gradual disintegration of iron rich intermetallic phases on base Al15(FeMn)3Si2, dissolution but also melting of intermetallic phases on base Al-Al2Cu-Si. Optimal solution treatment (515°C/4 hours) most improves mechanical properties. Further increases of solution time, leads to alloy elongations, while both, the tensile strength continuously drop. Practical implications: The present study is a part of larger research project, which was conducted to investigate and to provide a better understanding microstructure, heat treatment and mechanical properties of recycled (secondary) Al-Si cast alloy. Originality/value: The paper contributes to better understanding effect of the T4 heat treatment on the microstructure (morphology of eutectic silicon and intermetallic phases) and mechanical properties (tensile strength and Brinell hardness) of recycled cast alloy.

4

Ilościowa ocena kształtu krzemu eutektycznego w siluminach

Skočovsky P., Kiš M., Vaško A.

Archiwum Odlewnictwa

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2004

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R. 4, nr 11/2

160--165

PL

W artykule przedstawiono analizę możliwości oceny kształtu krzemu eutektycznego w siluminach na podstawie pomiarów współczynnika kształtu przy zastosowaniu analizy obrazowej. Omówiono przykłady zastosowania tej metodyki do oceny wpływu różnych czynników na strukturę i właściwości siluminów AlSi7Mg0,3 oraz AlSi10MgMn.

EN

The contribution deals with the analysis of possibilities of description of eutectic silicon shape in silumins on the basic of measurement of its shaped factor using the image analysis. The examples of using of presented methodics at evaluation of influence of different factors on the structure and properties of AlSi10MgMn and AlSi7Mg0.3 silumins are shown.

5

Wpływ obróbki cieplnej na mikrostrukturę siluminów

Gorockiewicz R.

Archiwum Odlewnictwa

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2003

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R. 3, nr 9

133--139

PL

Badano wpływ obróbki cieplnej siluminów na podatność krzemu eutektycznego do koalescencji i zaokrąglania się. Badania potwierdziły, że procesy koalescencji i zaokrąglania krzemu eutektycznego zachodzą łatwiej i szybciej, gdy cząsteczki krzemu eutektycznego w stanie przed obróbką cieplną są bardziej zdyspergowane.

EN

The influence of the heat-treatment of silumins on the susceptibility of the eutectic - Si to coalescence and sheroidise has been examined. Research confirmed that processes of coalescence and spheroidise of the eutectic - Si happen more easily and more quickly, when particles of the silicon before a heat-treatment are more dispercity.