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High Temperature Corrosion Performance of Carbon Steel Coated with Iron Aluminide in Mixture of O2 and SO2 Atmosphere

Omranian-Mohammadi P., Raiszadeh R., Shahverdi H. R.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

529--538

EN

In this investigation the surface of an aluminized sample of plain carbon steel was melted and alloyed using a tingsten inert gas (TIG) welding process to produce iron-aluminide intermetallic phases on the surface. The produced coating was then characterized by SEM and EDS and its high-temperature properties in O2 + 1%SO2 gas were examined. The results showed that the Fe3 Al coating produced could protect the substrate as it was subjected to the corroding gases at 700°C due to the formation of an alumina layer between the substrate and an outer layer of Fe2 O3 . At 900°C, the coating could only protect the substrate for 64 h. The lack of further protection at this temperature is attributed to the decrease in the protective properties of alumina with an increase in its temperature and the lack of presence of enough Al atoms in the coating for the repair of the defects formed in the alumina layer.

2

Kinetics of static recrystallization in the coarse-grained Fe–40 at.%Al–Zr–B alloy

Schindler I., Kopeček J., Kawulok P., Jabłońska M., Hadasik E., Jóźwik P., Opěla P., Hanus P., Polkowski W., Bojar Z.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 4

816--826

EN

The aim of works was to describe mathematically the kinetics of static recrystallization of the alloy type Fe–40 at.%Al–Zr–B (with 24.6 Al–0.01 B–0.18 Zr–0.01 C in wt.%) with the coarse-grained structure. The microstructure of the laboratory castings made of this extremely brittle alloy was homogenized by hot rolling of the material in the protective capsules and by the long-term annealing at 1200 °C. An initial microstructure with average grain size 0.77 ± 0.27 mm was obtained. Based on the isothermal plastic deformation tests and EBSD analysis, the static recrystallization kinetics of the prepared coarse-grained B2 iron aluminide after strain 0.20 was mathematically described. Recrystallized fraction depends on deformation/annealing temperature (900–1100 °C) as well as on annealing time. The activation energy of static recrystallization was calculated as 255 kJ mol−1. Competition between dynamic recovery and static recrystallization was proved after strain 0.35 and annealing temperature 1100 °C. Static recrystallization starts relatively easily in the studied alloy, but a very long-term annealing is quite necessary for the complete course of recrystallization. The mean size of recrystallized grains falls with the decreasing annealing temperature (0.47 ± 0.15 mm for temperature 1100 °C, and 0.22 ± 0.04 mm for 900 °C). Even at a temperature of 1200 °C the annealing after deformation should last approx. 1 min for obtaining the fully recrystallized microstructure. That is why the standard hot forming technologies should be combined by an interpass annealing in order to refine sufficiently the coarse grains.

3

Wpływ obróbki plastycznej na gorąco na właściwości mechaniczne stopów na osnowie fazy międzymetalicznej Fe3Al

Komorek Z., Jóźwiak S., Bojar Z.

Archiwum Odlewnictwa

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2006

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R. 6, nr 18/2

243--248

PL

W pracy przedstawiono wpływ obróbki plastycznej na gorąco na mikrostrukturę oraz właściwości wytrzymałościowe odlewniczego stopu na osnowie fazy międzymetalicznej Fe3Al. Zastosowana niekonwencjonalna obróbka plastyczna na gorąco skutecznie umożliwia kształtowanie badanych stopów na osnowie fazy Fe3Al oraz prowadzi do dwukrotnego rozdrobnienia ziaren. Rozdrobnienie to efektywnie wpływa na poprawę właściwości wytrzymałościowych; znacząco wzrasta wytrzymałość na ściskanie (o 200MPa) oraz plastyczność (o ponad 60%).

EN

Used orthodox hot working enables effective shaping of tested alloys based on Fe3Al and leads to twice refinement of microstructure.The refinement of microstructure in effective way increases mechanical properties, at about 10% increases plasticity in ambient temperature and at about 200MPa increases compressive strength and what is especially crucial for engineers applications increases the yield point up to 620MPa for FeAl16 alloy.

4

The effect of Al content on hydrogen absorption and mechanical properties of FeAl phase

Barcik J., Stępień K.

Advances in Materials Science

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2004

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Vol. 4, nr 1(5)

5--15

EN

The influence of the aluminium content in the FeAl phase on the absorption of hydrogen generating spontaneously or electrolytically from the surrounding environment, was determined. The ability of the FeAl phase to absorb hydrogen was examined in terms of the hydrogen content changes of the effective diffusion coefficient, and the resuls of the three-point bending as well as the hardness measurements.