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Microstructure investigations of cast Zn-Al alloys

Krupińska B., Rdzawski Z., Krupiński M., Labisz K.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 60, nr 1

15--22

EN

Purpose: The goal of the presented investigations was to evaluate to possibility of application of popular modifiers for chosen types of zinc alloys. The special aim of this work is to determine the influence of alloy modification on the crystallisation kinetics and microstructure of the cast zinc alloy. This research work presents also the investigation results of derivative thermoanalysis performed using the UMSA device. The material used for investigation was the ZnAl8Cu1 alloy. Design/methodology/approach: For phase determination there were used electron microscope techniques like SAD diffraction investigations which were carried out on the 200 kV transmission electron microscope. The UMSA (Universal Metallurgical Simulator and Analyser) device allows it to determine the specific melting process, influence of the cooling rate on the crystallization of phases and eutectics of the investigated alloys. Cooling rate influences the microstructure and properties of the investigated zinc cast alloys. Findings: Change of the crystallization kinetics allows it to produce materials with improved properties, which are obtained by: microstructure refinement, reduction or elimination of segregation. Research limitations/implications: The material was examined metallographically and analysed qualitatively using light and scanning electron microscope as well as the area mapping and point-wise EDS microanalysis. The performed investigation are discussed for the reason of an possible improvement of thermal and structural properties of the alloy. Practical implications: The investigated material can find its use in the foundry industry; an improvement of component quality depends mainly on better control over the production parameters Originality/value: Investigations concerning the development of optimal chemical composition and production method of zinc-aluminium alloys with selected rare earth metals with improved properties compared to elements made of alloys with appliance of traditional methods, will contribute to a better understanding of the mechanisms influencing the improvement of functional properties of the new.

2

Crystallisation kinetics of the Zn-Al alloys modified with lanthanum and cerium

Krupińska B., Rdzawski Z., Labisz K.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 46, nr 2

154--160

EN

Purpose: The aim of the investigation is to determine the influence of modification on crystallisation kinetics on microstructure of the cast zinc alloy. This research work presents also the investigation results of derivative thermoanalysis performed using the UMSA device. The material used for investigation was the ZnAl8Cu1 alloy. Design/methodology/approach: The UMSA device (Universal Metallurgical Simulator and Analyser) allows it to determine the characteristic points of the crystallised alloy including: determination of the influence of alloy modifiers, alloying additives, melting process parameters, cooling rate influence on phase and eutectics crystallisation of the investigated alloys. In was fund that cooling rate has an influence an microstructure and mechanical properties of the cast zinc alloys. Findings: Crystallisation kinetics change makes it possible to produce materials with improved properties, which are obtained by: microstructure refinement and decrease or elimination of the segregation phenomenon. Research limitations/implications: The material was examined metallographic and analysed qualitatively using light and scanning electron microscope as well as the area mapping and point-wise EDS microanalysis. The performed investigation are discussed for the reason of an possible improvement of thermal and structural properties of the alloy. Practical implications: The investigated material can find its use in the foundry industry; an improvement of component quality depends mainly on better control over the production parameters. Originality/value: value Investigation concerning the elaboration of optimal chemical composition and production method of zinc-aluminium alloys modified with chosen rare earths metals with enhanced properties compared to elements performed from traditional alloys and production methods, makes it possible to achieve a better understanding of mechanisms influencing improvement of mechanical properties of the new developed alloys.

3

Cooling rate and chemical composition influence on structure of Al-Si-Cu alloys

Krupiński M., Labisz K., Rdzawski Z., Pawlyta M.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 45, nr 1

13--22

EN

Purpose: The aim of this work is to perform the investigation of cooling rate influence as well as rare earth metals modification on microstructure of the AC-AlSi7Cu3Mg and AC-AlSi12CuNiMg cast aluminium alloys. In the work also artificial neural networks were applied for investigations of the influence of the alloying additives on the properties of the AC-4XXX alloy. Design/methodology/approach: In the work the thermo - derivative analysis was applied for the reason to determine changes occurred in the Al-Si-Cu alloy caused by cooling rate change in a range between 0.1 and 1.4°C/s as well chemical composition of the investigated alloy. Also artificial neural networks were applied for prediction of the chemical composition and heat treatment parameters and influence on mechanical properties of the investigated aluminium alloys. Findings: The performed investigation are discussed for the reason of an possible improvement of thermal and structural properties of the alloy. Practical implications: The aim of the carried out investigations was to work out a computer aided tool for prediction of mechanical properties on the basis of registered parameters during the technological process as well as controlling the process in real time, which can be useful for foundry and cast industry for achieving of material with assumed properties. Originality/value: Chemical composition and cooling rate applied for the alloy influences the crystallisation process of the phases and eutectics, and that fore also the microstructure and determines at the same time the properties of these aluminium alloys. The achieved results can be used also for liquid metal processing in science and industry and obtaining of a required alloy microstructure and properties influenced by a proper production conditions. The determination of the technological process parameters as well chemical composition allows it to predict the material properties.

4

Image analysis used for aluminium alloy microstructure investigation

Krupiński M., Labisz K., Dobrzański L. A., Rdzawski Z.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 42, nr 1-2

58-65

EN

Purpose: In this work the metallographic microstructure analysis of the investigated AlSi7Cu3Mg aluminium cast alloy was performed for samples cooled with different cooling rate settings. The preformed investigations are subjected to the analysis of cooling rate influence on the phase morphology. Design/methodology/approach: The solidification process itself is analysed using the UMSA device by appliance of the Derivative Thermo Analysis. The influence of the cooling rate on the alloy microstructure was investigated using computer aided image analysis, in this work also the content of particular phases was analysed, as well the percentage of pinholes compared to the chosen cooling rate. Findings: The treated sample is without holes, cracks and defects as well as has a slightly higher hardness value compared to the as-cast material. Research limitations/implications: The investigated samples were made of the cylindrical shape and were cooled in the range of 0.2°C/s to 1.25°C/s. In this work also the derivative thermoanalysis was performed to determine the correlation between the chosen cooling rate and the microstructure as well changes in the derivative curve shape. For alloy cooling with chosen cooling rate as well for the derivative thermo-analysis the UMSA analysator was applied. Practical implications: The investigated material can find its use in the foundry industry; an improvement of component quality depends mainly on better control over the production parameters. Originality/value: The originality of this work is based on applying of regulated cooling rate of aluminium alloy for structure and mechanical properties changes. As an effect of this study it will be possible to understand and to influence the mechanism of structure forming, refinement and nucleation. Also a better understanding of the thermal characteristics will be provided to achieve a desirable phase morphology required for application of this material under production conditions.

5

Structure investigation of the Al-Si-Cu alloy using derivative thermo analysis

Krupiński M., Labisz K., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 34, nr 1

47-54

EN

Purpose: This research work presents the investigation results of derivative thermoanalysis performed using the UMSA device (Universal Metallurgical Simulator and Analyzer). The material used for investigation was an Al-Si-Cu alloy known as AC-AlSi7Cu3Mg grade aluminium cast alloy. Design/methodology/approach: As a result of this research the cooling rate influence on structure and mechanical properties changes, especially HB Hardness was investigated. The cooling rate was set in a variable range of ~0.2 oC/s to ~1.25 oC/s. In this work structure changes were determined concerning the structure, especially the dendrites and grains and particle distribution in the aluminium matrix. Findings: The reason of this work was to determine the optimal cooling rate values, to achieve good mechanical properties for protection of this aluminium cast alloy from losing their work stability and to make it more resistant to action in hard working conditions. For investigations of the aluminium samples hardness measurements of the different sample areas were performed. The material was examined metallographically and analyzed qualitatively using light and scanning electron microscope as well as the area mapping and point-wise EDS microanalysis. The performed investigation are discussed for the reason of an possible improvement of thermal and structural properties of the alloy. The investigation revealed the formation of aluminium reach (. -Al) dendrites and also the occurrence of the .+ß eutectic, the ternary eutectic .+Al2Cu+ß, as well the occurrence of the Fe and Mn containing phase was confirmed. Practical implications: In the metal casting industry, an improvement of component quality depends mainly on better control over the production parameters. Originality/value: This work provides also a better understanding of the thermal characteristics and processes occurred in the new developed near eutectic Al–Si-Cu alloy. The achieved results can be used for liquid metal processing in science and industry and obtaining of a required alloy microstructure and properties influenced by a proper production conditions.

6

Phases morphology and distribution of the Al-Si-Cu alloy

Labisz K., Krupiński M., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 37, nr 2

309-316

EN

Purpose: In this paper results of phase morphology investigation are presented of a newly developed Al-Si-Cu alloy. Such studies are of great interest for the metal casting industry, mainly the automotive industry, where improvement of cast elements quality is crucial for economic and quality reason and depends mainly on properly performed controlling process of the production parameters Design/methodology/approach: The basic assumptions of this work are realised with Universal Metallurgical Simulator and Analyzer. The solidification process itself is analysed using the UMSA device using the Derivative Thermo Analysis. Findings: During the investigation the formation of aluminium reach (á-Al) dendrites was revealed and also the occurrence of the á+â eutectic, the ternary eutectic á+Al2Cu+â, as well as iron and manganese containing phase was confirmed. This work shows that the thermal modification of the Al-Si-Cu can be quantitatively assessed by analysis of the microstructure evaluation as well as of the cooling curve thermal characteristics. Research limitations/implications: The investigations were performed using standard metallographic investigation as optical, scanning and transmission electron microscopy methods; also the EBSD phase identification method based on the kikuchi lines identification was used. The results in this paper are valuable only for the Al2Cu, Fe and Mg containing phases, and are not performed for the assessment of the Silicon Modification Level. Practical implications: As an effect of this study it will be possible to understand and to influence the mechanism of structure forming, refinement and nucleation. Also better understanding of the thermal characteristics will be provided to achieve a desirable phase morphology required for specific application of this material under production conditions. Originality/value: The originality of this work is based on applying of regulated cooling rate of aluminium alloy for structure and mechanical properties changes. In this work the dependence among the regulated cooling speed, chemical composition and structure of the investigated aluminium cast alloy on the basis of the thermo-analysis was presented.

7

Porównanie metod badania krzepnięcia i krystalizacji stopów metali

Wasilewski P.

Archiwum Odlewnictwa

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2003

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R. 3, nr 10

323--337

PL

W artykule przedstawiono rys historyczny oraz omówiono i porównano 6 metod badań krzepnięcia i krystalizacji stopów metali na przykładzie stopów aluminium: metodę Analizy Termicznej (AT), metodę Analizy Termiczno-Różnicowej (DTA), metodę Analizy Termiczno-Derywacyjnej (ATD), metodę Analizy Elektro-Derywacyjnej (AED), zespoloną metodę Analizy Termiczno-Derywacyjnej i Elektro-Derywacyjnej (ATD-AED) i metodę Analizy Termiczno-Napięciowo-Derywacyjnej (ATND). Przedstawiono zalety i wady porównywanych metod oraz podano przykładowo wyniki analiz dla różnych siluminów.

EN

In the article introduced historic and talk overed and one compared 6 methods of investigations solodification and crystallization alloys of metals on example of the aluminium alloys: method of Thermal Analysis (AT), method of Analysis Thermal-Difference ( DTA), method of Analysis Thermal-Derivation( ATD), method of Analysis Electrical-Derivation(AED), joint method of Analysis Thermal-Derivation and Electrical-Derivation(ATD-AED) and method of Analysis Thermal-Napięciowo-Derivation( ATND). Introduced advantages and defects compared of methods and gave for example results of analysises for different aluminium alloys.