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1

Structure formation of AlMg2-AlN composite cast in electromagnetic field

Cholewa M., Formanek B., Sozańska M., Staszewski M.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 25, nr 1

59-62

EN

Purpose: Basic material concept, technology and some results of studies on aluminum matrix composite with dispersive aluminum nitride reinforcement was shown. Studied composites were manufactured with use f ex-situ technique and powder metallurgy. Design/methodology/approach: Aluminum nitride powder was manufactured in process of self-evolving high-temperature synthesis SHS. Composite powder Al-AlN was obtained using mechanical alloying. Composite castings were manufactured in stir casting process and poured into graphite moulds under external electromagnetic field. For powder and composite structure characterization some methods were used, including: light microscopy, scanning microscopy, X-ray analysis, characteristic X-radiation analysis and quantitative analysis of selected composite regions. Composite structure and reinforcement distribution was compared with use of quantitative analysis. Findings: Morphology and diffraction pattern of aluminum nitride powder was shown. Typical structure of studied composites with microanalysis results was indicated. Influence of electromagnetic field on structure and aluminum nitride dispersion change was represented. Practical implications: Application of joint casting technique, powder metallurgy and electromagnetic field enabled control of reinforcement dispersion as well as the metal matrix structure. Originality/value: Studies results confirmed the concept proposed for composite manufacturing.

2

Model of heat flow during crystallization of cast composites

Cholewa M.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 25, nr 2

51-56

EN

Purpose: The aim of this work was to show possibilities of numerical simulation software, based on heat transfer model, commonly used in foundry industry in cast composite properties engineering. Design/methodology/approach: The main restriction in most of used software systems is lack of heat transfer, which may occur at composite creation. In this work the reinforcing particle morphology an size were expressed by one quantity - morphological modulus Mm and were examined for influence on heat transfer and conductivity up to the Newton's and Fourier's laws. Findings: The main restrictions for using Fourier's model based software for composite engineering are shown. The way for crystallization control was presented including influence of morphology, transition zone and thermo-physical properties of components. Research limitations/implications: Proposed methodology can be used for cast composite properties engineering in cases, where relative motion of components is negligible. In other cases heat transfer coefficient is justified only if the software used is based on Fourier's model and the source code is accessible. Originality/value: Proposed assumptions create possibility for components selection verification in terms of technological and operating properties of cast composite. An example of such approach was shown in work.

3

Heat flow description during crystallization process of cast dispersive composites

Cholewa M.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 1

117-122

EN

The aim of this work was to show possibilities of numerical simulation software, based on heat transfer model, commonly used in foundry industry in cast composite properties engineering. The main restriction in most of used software systems is lack of heat transfer, which may occur at composite creation. In this work the reinforcing particle morphology an size were expressed by one quantity – morphological modulus Mm and were examined for influence on heat transfer and conductivity up to the Newton's and Fourier's laws. The main restrictions for using Fourier's model based software for composite engineering are shown. The way for crystallization control was presented including influence of morphology, transition zone and thermo-physical properties of components. Proposed methodology can be used for cast composite properties engineering in cases, where relative motion of components is negligible. In other cases heat transfer coefficient is justified only if the software used is based on Fourier’s model and the source code is accessible. Proposed assumptions create possibility for components selection verification in terms of technological and operating properties of cast composite. An example of such approach was shown in work [1, 23].

4

Thermal verification procedure for dispersive composite solidification process

Cholewa M.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 16, nr 1-2

80--87

EN

Purpose: The aim of this work was optimization of composite matrix solidifcation process with use of thermal properties of components and geometrical characteristics of transition zone related with reinforcing particles morphology. Design/methodology/approach: The method was based on quantitive image analysis. The reinforcing particles morphology was described by morphological modulus. With use of numerical simulation the changes in temperature and its derivatives after time and direction in studied composite micro-region appeared. Findings: As a result of this studies the forecast procedure for composite structure evaluation was obtained and for which optional solidification theory can be used. Analysis of particles morphology influence on matrix solidification process is a proposed novelty. Research limitations/implications: The work enables in enginereeng practice verification of components from technological point of view by thermal and geometrical properties selection and thus by introducing changes to the particle – matrix (casting) – mould – surrounding system. In this stage the procedure does not include the diffusion between matrix and reinforcement related to its relative motion. Evaluation of incomplete wetting and transition zone phases occurance does not permit tribological or fatique properties forecasting. Originality/value: The proposed procedure is useful for composite properties forecasting based on components thermal and geometrical characteristics.

5

New approach to cast dispersive composite engineering

Cholewa M.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 18, nr 1-2

63--66

EN

Purpose: The aim of this work was to show possibilities of numerical simulation software, based on heat transfer model, commonly used in foundry industry in cast composite properties engineering. Design/methodology/approach: The main restriction in most of used software systems is lack of heat transfer, which may occur at composite creation. In this work the reinforcing particle morphology an size were expressed by one quantity - morphological modulus Mm and were examined for influence on heat transfer and conductivity up to the Newton’s and Fourier’s laws. Findings: The main restrictions for using Fourier’s model based software for composite engineering are shown. The way for crystallization control was presented including influence of morphology, transition zone and thermophysical properties of components. Research limitations/implications: Proposed methodology can be used for cast composite properties engineering in cases, where relative motion of components is negligible. In other cases heat transfer coefficient is justified only if the software used is based on Fourier’s model and the source code is accessible. Originality/value: Proposed assumptions create possibility for components selection verification in terms of technological and operating properties of cast composite. An example of such approach was shown in work [1].