Structure and Properties of Fe–Al–Si Alloy Prepared by Mechanical Alloying

Novák, Pavel; Vanka, Tomáš; Nová, Kateřina; Stoulil, J.; Průša, Filip; Kopeček, Jaromı́r; Haušild, Petr; Laufek, František

doi:10.3390/ma12152463

Cited by 21 publications

(33 citation statements)

References 47 publications

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“…The motivation for these tests was the enormously high room-temperature brittleness of the FeAl20Si20 alloy. At high temperatures, the toughness of the alloy was much better, and the alloy even exhibited a limited plasticity [16]. On the other hand, the FeAl20Si20 alloy did not resist sudden changes of temperature, which was already visible during cooling from the SPS process temperature.…”

Section: Discussionmentioning

confidence: 98%

“…When nickel was added, the Fe2Al5 phase disappeared (Figures 1, 2b and 4). It could have a beneficial effect on fracture toughness, because the Fe2Al5 phase is known as highly brittle, just like Fe3Al2Si3 in a high-silicon FeAl20Si20 alloy, which was recently investigated [16]. According to the optical microscopy and EDS map (Figure 4), the silicides also completely disappeared when the nickel was added.…”

Section: Microstructure and Phase Compositionmentioning

confidence: 99%

“…Titanium negatively influenced oxidation behavior and wear resistance because of the presence of titanium dioxide in the oxide layer and the brittle silicides that caused chipping wear, respectively. plasma sintering [16]. The alloys exhibited a very good oxidation resistance at high temperatures-much better than binary Fe-Al and Fe-Si alloys [17].…”

mentioning

confidence: 99%

“…The improvement of oxidation resistance does not lie in the incorporation of silicon to the oxide layer in a significant amount; rather, it lies in the formation of large volume fraction of silicides under the oxide layer, when aluminum diffuse to the surface in order to form Al 2 O 3 . Additionally, it has been found that the presence of silicon reduces the amount of iron oxide in scales, causing their better adherence to a substrate due to a more favorable Pilling-Bedworth ratio [16]. However, the FeAl20Si20 alloy is very brittle.…”

mentioning

confidence: 99%

“…However, the FeAl20Si20 alloy is very brittle. Powder metallurgy methods, including our high-energy mechanical alloying [18] and spark plasma sintering, allowed for an increase in the fracture toughness, but the values at room temperature still reached the parameters of brittle ceramics, i.e., approximately 3.5 MPa.m 1/2 [16]. Due to these parameters, the alloy could be applicable as a protective coating rather than as a bulk material.In recent research, we studied the high-temperature oxidation resistance of Fe-Al-Si alloys and its dependence on the Al:Si ratio, and we found that the 35:5 provided almost the same oxidation performance [17].…”

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confidence: 99%

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Effect of Nickel and Titanium on Properties of Fe-Al-Si Alloy Prepared by Mechanical Alloying and Spark Plasma Sintering

et al. 2020

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F.P.) 2 SVÚOM s.r.o., U Měšt'anského pivovaru 934/4, Abstract: This paper describes the structure and properties of an innovative Fe-Al-Si alloy with a reduced amount of silicon (5 wt. %) in order to avoid excessive brittleness. The alloy was produced by a combination of mechanical alloying and spark plasma sintering. Nickel and titanium were independently tested as the alloying elements for this alloy. It was found that wear resistance, which reached values comparable with tool steels, could be further improved by the addition of nickel. Nickel also improved the high-temperature oxidation behavior, because it lowers the liability of the oxide layers to spallation. Both nickel and titanium increased the hardness of the alloy. Titanium negatively influenced oxidation behavior and wear resistance because of the presence of titanium dioxide in the oxide layer and the brittle silicides that caused chipping wear, respectively. plasma sintering [16]. The alloys exhibited a very good oxidation resistance at high temperatures-much better than binary Fe-Al and Fe-Si alloys [17]. The improvement of oxidation resistance does not lie in the incorporation of silicon to the oxide layer in a significant amount; rather, it lies in the formation of large volume fraction of silicides under the oxide layer, when aluminum diffuse to the surface in order to form Al 2 O 3 . Additionally, it has been found that the presence of silicon reduces the amount of iron oxide in scales, causing their better adherence to a substrate due to a more favorable Pilling-Bedworth ratio [16]. However, the FeAl20Si20 alloy is very brittle. Powder metallurgy methods, including our high-energy mechanical alloying [18] and spark plasma sintering, allowed for an increase in the fracture toughness, but the values at room temperature still reached the parameters of brittle ceramics, i.e., approximately 3.5 MPa.m 1/2 [16]. Due to these parameters, the alloy could be applicable as a protective coating rather than as a bulk material.In recent research, we studied the high-temperature oxidation resistance of Fe-Al-Si alloys and its dependence on the Al:Si ratio, and we found that the 35:5 provided almost the same oxidation performance [17]. Since silicon is listed as a critical raw material in the EU [19], the minimization of its amount is reasonable. In a parallel research, our team studied Ti-Al alloys and proved that silicon also improves their oxidation behavior and reinforces the material by forming hard Ti 5 Si 3 silicides [20]. On the other hand, nickel is known to form stable aluminides rather than silicides [21].Therefore, this work aimed at a possible improvement of the properties of a lower-silicon FeAl35Si5 alloy by the addition of titanium as the expected silicide-forming element and nickel as the probable aluminide stabilizer. The tests were intended to study the high temperature oxidation behavior, basic mechanical properties, and tribological properties. Materials and Methods

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Section: Discussionmentioning

confidence: 98%

Section: Microstructure and Phase Compositionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Effect of Nickel and Titanium on Properties of Fe-Al-Si Alloy Prepared by Mechanical Alloying and Spark Plasma Sintering

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Oxidation Behaviour of Fe-28Al-5Si at.% Alloyed with Ti and Mo

Hotař,

Vodičková,

Pazourková Prokopčáková

et al. 2024

JOM

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The high-temperature oxidation behaviour of Fe-28Al-5Si, Fe-28Al-5Si-2Mo and Fe-28Al-5Si-2Ti (in at.%) was investigated. Cyclic oxidation tests of iron aluminides were performed at 900°C and 1100°C. The oxidation kinetics and oxidation behaviour (by measuring of total weight gain, etc.) were described. The structure of the alloys’ surfaces after oxidation, as well as the composition and morphology of oxide layers, was analysed by optical microscopy, scanning electron microscopy, SEM–EDS and X-ray diffraction. The beneficial effect of alloying with titanium or molybdenum on the oxidation resistance of Fe-Al-Si-based alloys was observed at temperatures of 900°C and 1100°C. Titanium and molybdenum suppress the formation of eutectic regions of the secondary phase in the structure, which preferentially oxidize. Therefore, a thin and compact alumina layer (only minor amounts of iron oxides and ZrO2) formed on the surface of Fe-28Al-5Si-2Mo and Fe-28Al-5Si-2Ti at 900°C. These alloys maintain low weight gains even at a temperature of 1100°C. On the other hand, alloy Fe-28Al-5Si contains a high number of eutectics-like areas, which causes ingress of the oxidation (selective oxidation of eutectic areas) and breakaway oxidation is observed at 900°C and 1100°C, respectively.

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