Fraktografie kompozitů (MMC) vyrobených difuzí Ni do Al

Fractography of MMC produced by difusion of Ni into Al

conference paper

en

The specimens were prepared by diffusion of Ni from plasma-sprayd coating into the Al substrate at 630oC. Specimens with different fraction of Al-Ni intermetallic particles and eventually of eutectic Al+Al3Ni were prepared. Mechanical properties of these specimens were tested at room temperature (tensil tests) and higher temperatures (creep tests at 200 – 400oC). Ligh microscopy, image analysis, SEM and EDS microanalysis were been concluded that at room temperature "weak" structure elements are the particles of Al3Ni intermetallic compound. Due to their "premature" fracture, the deformation properties (e.g., elongation) deteriorate considerably. The increase of strength characteristics is thus counteralanced by drop of plasticity. Creep test, on the other hand, showed improvement of creep characteristics (creep rate, creep strength) at low stresses.The fracture is ductile with discontinuites at interfaces between different structural elements (particles/matrix or layers of eutectics/pure Al).

Vzorky byly připraveny pomocí difúze Ni z plasmaticky naneseného povlaku do hliníkového substrátu při 630oC. Tímto způsobem byly připraveny vzorky s různým objemovým podílem intermetalické fáze Ni-Al, případně eutektika Al + Ni3Al. Na těchto vzorcích byly zkoumány mechanické vlastnosti – při pokojové teplotě zkouška tahem, – při vyšších teplotách (200 – 400oC) pak creepová zkouška. Pro zkoumání jemných strukturních elementů bylo použito světelné mikroskopie, obrazové analýzy a SEM a EDS mikroanalýzy.

The specimens were prepared by diffusion of Ni from plasma-sprayd coating into the Al substrate at 630oC. Specimens with different fraction of Al-Ni intermetallic particles and eventually of eutectic Al+Al3Ni were prepared. Mechanical properties of these specimens were tested at room temperature (tensil tests) and higher temperatures (creep tests at 200 – 400oC). Ligh microscopy, image analysis, SEM and EDS microanalysis were been concluded that at room temperature "weak" structure elements are the particles of Al3Ni intermetallic compound. Due to their "premature" fracture, the deformation properties (e.g., elongation) deteriorate considerably. The increase of strength characteristics is thus counteralanced by drop of plasticity. Creep test, on the other hand, showed improvement of creep characteristics (creep rate, creep strength) at low stresses.The fracture is ductile with discontinuites at interfaces between different structural elements (particles/matrix or layers of eutectics/pure Al).

composite, fracture, Al alloy, creep, tensile test, fractography

25.04.2001

Hutnická fakulta Technickem univerzity v Hošiciach v spolupráci s Ústavom materiálového výškumu SAV v Košiciach

Stará Lesná, High Tatra Mountains, Poprad, Slovak republic

80-7099-324-3

Metallography 01

118–121

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