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Cavitation Erosion Resistance Of FeAl Intermetallic Alloys And Al2O3 – Based Ceramics

Jasionowski R., Pędzich Z., Zasada D., Przetakiewicz W.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2A

671--675

EN

The problem of the devastation of fluid-flow machinery components is very complex, because it consists of processes of erosion and corrosion. The most dangerous factor is the cavitation phenomenon, which is very difficult to eliminate through the use of design solutions. Usage of materials with greater resistance to cavitation erosion seems to be an obvious effective method of prevention. Such materials as FeAl intermetallic alloys and ceramic materials may be considered as reasonable candidates for this purpose. In the presented work, cavitation erosion resistance of FeAl intermetallic alloys and Al2O3 – based ceramic materials, was investigated and compared.

PL

Problem niszczenia elementów maszyn przepływowych jest bardzo złożony, ponieważ składa się z procesów erozyjnych i korozyjnych. Najbardziej niebezpiecznym czynnkiem jest zjawisko kawitacji, które bardzo trudno jest wyeliminować poprzez stosowanie rozwiązań konstrukcyjnych. Skutecznym rozwiązaniem jest stosowanie materiału o większej odporności na erozję kawitacyjną. Takimi materiałami mogą być stopy intermetaliczne FeAl lub materiały ceramiczne. W pracy przedstawiono porównanie odporności na erozję kawitacyjną stopów intermetalicznych FeAl i materiałów ceramicznych na bazie Al2O3.

2

The effect of aluminum content on the microstructure and cavitation wear of feal intermetallic alloys

Jasionowski R., Zasada D., Polkowski W.

Acta Mechanica et Automatica

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2014

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Vol. 8, no. 1

49--52

EN

Intermetallic-based alloys (so called intermetallics) of the Fe-Al binary system are modern construction materials, which in re- cent decades have found application in many branches of the power, chemical and automotive industries. High resistance of FeAl based alloys to cavitational erosion results first of all from their high hardness in the as-cast state, large compressive stresses in the material, as well as homogeneous structure. In the present paper, the effect of aluminum content on the microstructure, texture and strain imple- mented upon cavitation wear of FeAl intermetallic alloys, have been analyzed by field emission gun scanning electron microscopy (FEG SEM) and electron backscatter diffraction (EBSD) analysis. Obtained results of structural characterization indicates that with increasing aluminium content effects of orientation randomization (weakening of <100>//ND casting texture), grain refinement and rising of mechani- cal strenght (and so cavitational resistance) take place.

3

Influence of Heat Treatment on the Structure and Mechanical Properties of Ni3Al - Based Alloys

Jóźwik P., Bojar Z.

Archives of Metallurgy and Materials

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2010

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Vol. 55, iss. 1

271-279

EN

This study iiwestigates two Ni3Al - based intermetallic alloys containing differing amounts of zirconium, boron and chromium. Gradual homogenisation was accomplished through long-lasting annealing, up to 100 hours, at 1000°C or 1200°C in air or argon atmospheres. A higher level of homogeneity of the cast without chromium alloy was obtained in comparable heat treatment conditions. Annealing temperaturę has an essential influence on the homogenisation process of the investigated alloys. This influence is much morę essential than annealing time and environmental conditions. These treatment conditions are critical for microstructure, as well as the properties of the investigated alloys. For matched conditions of plastic working an optimum level of strain hardening was obtained . This did not cause a loss of cohesion in the investigated alloys, but it was sufficient to start a recrystallisation process. The fine-grained structure of the investigated alloys is responsible for the improvement in their mechanical properties.

PL

W pracy przedstawiono badania dwóch stopów na osnowie fazy międzymetalicznej Ni3Al o różnej zawartości cyrkonu, boru i chromu. Długotrwałe wygrzewanie w czasie do 100 godzin w temperaturze 1000°C i 1200°C w atmosferze powietrza lub argonu prowadzi do stopniowego ujednorodnienia składu fazowego badanych materiałów. W porównywalnych warunkach obróbki cieplnej uzyskano, dla materiału bez zawartości chromu zdecydowanie większy poziom jednorodności. Stwierdzono, że temperatura wygrzewania ma istotnie większy wpływ niż czas procesu na strukturę i właściwości badanych stopów. Ściśle określone parametry obróbki plastycznej pozwoliły na uzyskanie, bez utraty spójności, poziomu umocnienia wystarczającego do zajścia procesu rekrystalizacji w całej objętości badanych materiałów. Tak uzyskana, drobnoziarnista struktura osnowy badanych stopów istotnie polepsza ich własności wytrzymałościowe.

4

Microstructure and properties of the Al2O3-Ti3AlNb composites.

Samsel K., Garbacz H., Kurzydłowski K.J.

Archives of Materials Science

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2005

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Vol. 26, nr 3

207-219

EN

The study was concerned with the Al2O3-Ti3AlNb composites produced by powder metallurgy. The microstructures of the sintered composites were described qualitatively and quantitatively. The physical and mechanical properties of the samples examined during the experiments included: porosity, hardness, elastic modulus and brittle toughness. It has been shown that the properties of the composites depend not only on their constituents but also on the particular features of their microstructural structure, which in turn depend on the technology employed. The properties of the composites appeared to be intermediate between those of ceramics and those of alloys with intermetallic matrix. They depend, in a non-linear way, on the volumetric shares of the ceramics and the specific surface area of the phase boundaries. The deviations from the linear theory of mixing can be explained in terms of the disintegrated intermetallic precipitates and pores. It has also been found that with increasing volumetric share of the ceramic material, the sizes of the pores and of the intermetallic particles decrease, whereas their shapes remain almost unchanged.