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TEM microstructure investigations of aluminium alloys used for laser alloying

Labisz K., Kurpiński M, Tański T.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

734--741

EN

Purpose: In this paper there are presented results of Transmission Electron Microscope investigation concerning the structure of the AlSi7Cu4 cast aluminium alloy using for alloying and remelting with the high power diode laser (HPDL). There are also presented the results of the thermo-derivative analysis performed using the UMSA (Universal Metallurgical Simulator and Analyser) device, allowing to determine the specific points of the solidifying alloy, what is helpful for phase determination occurred in this alloy. In this work especially the changes of the precipitation type, size and shape were determined. Design/methodology/approach: The investigations were performed using electron microscopy for the microstructure and phases determination. By mind of the transmission electron microscopy, especially selected area diffraction method appliance it was possible to determine the phases occurred in the alloy in the as cast state. The morphology and size of the Mg2Si was also possible to determine as well the lattice parameters for this phase. Findings: The reason of this work was also to present the laser treatment technology, which will be used for further alloying and remelting with ceramic powders - especially carbides and oxides. Particularly the overview will be directed on the laser power to achieve good layer hardness for protection of this hot work tool steel from losing their work stability and to make the tool surface more resistant to action in external conditions. The structure of the surface laser tray changes in a way, that there are very high roughness of the surface zone and the flatness or geometry changes in an important manner, crucial for further investigation. Research limitations/implications: The aluminium samples were examined metallographically using transmission electron microscope with different image techniques. Practical implications: Developing of new technology with appliance of Al alloys, High Power Diode Laser and diverse ceramic powders will be possible to obtain, based in findings from this research project. Some other investigation should be performed in the future, but the knowledge found in this research concerning the proper process parameters for each type of alloy shows an interesting investigation direction. Originality/value: The combination of metallographic investigation for cast aluminium alloys - including electron microscope investigation - and HPDL treatment parameters makes the investigation very attractive for automobile, aviation industry, and others where aluminium alloys plays an important role.

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Influence of thermo-derivative analysis conditions on microstructure of the Al-Si-Cu alloy

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

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 2 spec.

19--22

EN

Microstructure change of the metals and alloys as a result of variable crystallisation conditions also by mind of cooling rate change influence the mechanical properties. In this work there are presented the interdependences between the cooling rate, chemical composition and microstructure of the cast aluminium alloy Al–Si–Cu as a result of the thermo-derivative analysis, using the UMSA (Universal Metallurgical Simulator and Analyzer) device. An important tool for the microstructure evaluation of the Al type AC-AlSi7Cu3Mg alloy was the light and electron scanning microscopy technique.

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Derivative thermo-analysis application to assess the cooling rate influence on the microstructure of Al-Si alloy cast

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

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 38, nr 2

115-122

EN

Purpose: The application of the UMSA device (Universal Metallurgical Simulator and Analyzer) has allow to determine the liquidus/solidus thermal points of solidified alloy, as well the thermal points, where phase- or eutectic crystallisation occurs. Design/methodology/approach: Investigations were performed using cast aluminium-silicon alloys, known as EN AC-4XXXX according to the PN-EN 1706:2001 standard. The solidification process was investigated using the metallurgical UMSA simulator connected to recording devices equipped with simulating cooling system. For the alloy microstructure investigation the optical microscope and transmission and scanning electron microscope with EDS equipment were used for evaluation of the chemical composition of the phases occurred in the investigated alloy. Findings: Investigation of the interdependences occurred between phase morphology and cooling rate using thermo-analysis has given the main results. Practical implications: In the metal casting industry the improvement of the quality of components depends mainly on proper control over the production parameters. Originality/value: The performed investigations allow to determine the microstructure changes as well the derivative curves in comparison to the cooling rate applied for the alloy.