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1
Content available Corrosion Behavior of FeAl and Fe3Al Based Fe-Al-C Alloys in Sulfuric Acid
Silva A. P., Brito P. P., Martins N.
Archives of Foundry Engineering
|
2022
|
Vol. 22, iss. 2
77--82
EN
Iron aluminides are iron-aluminum alloys that have excellent resistance to oxidation at high temperatures with low density, high resistance/weight ratio and a low manufacturing cost. Due to its characteristics, these alloys are presented as an option to replace stainless steels in certain applications. This works intends report the casting process and subsequent analyses involving microstructure, mechanical properties, and corrosion resistance of two Fe-Al-C alloys (Fe-11wt%Al and Fe-25wt%Al, containing 0.31-0.37%C), which were prepared in an induction furnace and poured in a permanent mold. Samples of these alloys were characterized and presented elevated hardness values of 37 HRC (alloy Fe-11wt%Al) and 49.6HRC (alloy Fe-25wt%Al) and microstructure with aluminides type Fe3Al and FeAl and also carbides type K. The Fe-11wt%Al alloy exhibited superior resistance to uniform corrosion, although both Fe-Al-C alloys exhibited significantly higher corrosion rates compared to a binary iron aluminide in 0.5M H2SO4 containing naturally dissolved oxygen.
2
The influence of heating rate during sintering on mechanical properties of Fe40Al sinters at room temperature
Siemiaszko D., Nowakowska I., Komorek Z.
Inżynieria Materiałowa
|
2016
|
Vol. 37, nr 5
267--271
EN
The results of a uniaxial compression test of Fe40Al (at. %) sintered powders are presented. Compression yield stress Rc0.2, ultimate strength Rcm, permanent deformation, and true compression strength at the maximum force point were determined. All Fe40Al sinters behaved like a plastic material; they were not brittle, and the sample after the compression test did not fall apart and was barrel-shaped. Observations of the microstructure revealed plastically-deformed grains. The obtained sinters were characterized by very high ultimate compressive strength (ok. 2700÷2800 MPa) and low yield stress (Rc0.2 approx. 280 MPa). This paper presents also XRD analyses, microstructure, and density of Fe40Al sinters.
PL
Podstawowym celem pracy było zbadanie wpływu szybkości nagrzewania podczas spiekania na właściwości mechaniczne spieków Fe40Al. W pracy zaprezentowano wyniki analizy dyfrakcji rentgenowskiej, pomiary gęstości, twardości sposobem Vickersa (HV0,5), a także właściwości wytrzymałościowe uzyskane w próbie ściskania.
3
Content available Optimization of Laboratory Hot Rolling of Brittle Fe-40at.%Al-Zr-B Aluminide
Schindler I., Hadasik E., Kopeček J., Kawulok P., Fabík R., Opěla P., Rusz S., Kawulok R., Jabłońska M.
Archives of Metallurgy and Materials
|
2015
|
Vol. 60, iss. 3A
1693--1701
EN
Use of the protective steel capsules enabled to manage the laboratory hot flat rolling of the extremely brittle as-cast aluminide Fe-40at.%Al-Zr-B with the total height reduction of almost 70 %. The hot rolling parameters were optimized to obtain the best combination of deformation temperature (from 1160°C up to 1240°C) and rolling speed (from 0.14 m·s−1 to 0.53 m·s−1). The resistance against cracking and refinement of the highly heterogeneous cast microstructure were the main criteria. Both experiments and mathematical simulations based on FEM demonstrated that it is not possible to exploit enhanced plasticity of the investigated alloy at low strain rates in the hot rolling process. The heat flux from the sample to the working rolls is so intensive at low rolling speed that even the protective capsule does not prevent massive appearance of the surface transverse cracking. The homogeneity and size of product’s grain was influenced significantly by temperature of deformation, whereas the effect of rolling speed was relatively negligible. The optimal forming parameters were found as rolling temperature 1200°C and the rolling speed 0.35 m·s-1. The effective technology of the iron aluminide Fe-40at.% Al-Zr-B preparation by simple processes of melting, casting and hot rolling was thus established and optimized.
PL
Zastosowanie ochronnych stalowych kapsuł pozwoliło na przeprowadzenie laboratoryjnego walcowania na gorąco pasm z niezwykle kruchego odlewanego aluminidku żelaza (stopu na osnowie fazy międzymetalicznej) Fe-40at.%Al-Zr-B, które umożliwiło redukcję wysokości o prawie 70%. Parametry walcowania na gorąco były dostosowywane celem uzyskania korzystnego zakresu temperatury odkształcenia (od 1160°C do 1240°C) oraz prędkości walcowania (od 0.14 m·s−1 do 0.53 m·s−1) dla otrzymania pasma bez pęknięć i rozdrobnienia silnie niejednorodnej mikrostruktury odlewu. Zarówno eksperymenty jak i matematyczne symulacje oparte na MES wykazały, że niemożliwe jest uzyskanie dobrej plastyczności badanego stopu przy niskich prędkościach odkształcenia podczas walcowania na gorąco. Strumień ciepła płynący z próbki na walce jest tak intensywny przy małej prędkości walcowania, że nawet kapsuła ochronna nie zapobiega pojawieniu się powierzchniowych pęknięć poprzecznych. Jednorodność i rozmiar ziarn w materiale silnie zależy od temperatury odkształcenia, podczas gdy wpływ prędkości walcowania jest relatywnie niewielki. Optymalne parametry kształtowania stopu to: temperatura 1200°C oraz prędkość walcowania 0.35 m·s−1. Skuteczna technologia przygotowania aluminidku żelaza Fe-40at.%Al-Zr-B w prostym procesie topienia, odlewania i walcowania na gorąco została w ten sposób ustalona i zoptymalizowana.
4
Content available Point defects in the B2 - phase region of the Fe-Al system studied by Mössbauer spectroscopy and X-ray diffraction
Hanc-Kuczkowska A.
Nukleonika
|
2013
|
Vol. 58, No. 1
123-126
EN
In this work Mössbauer spectroscopy and X-ray powder diffraction was used to study of point defects formation in intermetallic phases of the B2 structure of the Fe-Al system as a function of Al concentration. The results are compared with the concentrations of point defects determined from positron annihilation data. The values of the 57Fe isomer shift and quadrupole splitting for the components describing the point defects in the local environment of a Mössbauer nuclide are presented. The concentration of the Fe vacancies and Fe atoms substituting Al (i.e. anti-site atom, Fe-AS) are determined. The results show that an increase in Al content causes an increase in vacancy and Fe-AS concentrations.
5
Content available Effect of Ti, Nb, Cr and B on structure and mechanical properties of high aluminium cast iron
Kopyciński D.
Archives of Foundry Engineering
|
2013
|
Vol. 13, iss. 1
77--80
EN
In this work, a method was investigated to eliminate the presence of undesirable Al4C3 phases in a high-aluminium alloys, and thus improve the production process. The melting conditions employed in this work enabled the formation of a Fe-Al-C liquid solution. Moreover, titanium additions into the liquid allowed the precipitation of TiC. According to this reaction, the extent of carbon removal from the melt is strongly influenced by the amount of Ti additions. Hence, proper titanium levels can result in total removal of carbon from the liquid. Notice from this figure that Ti additions above 4.5%, totally eliminate the undesirable Al4C3 precipitates. Making Cr, Ti, B additions reduces size of FeAl alloys grains. In addition, this work indicates that the high-aluminium cast iron posses high oxidation resistance, exceeding that of high-chromium cast iron and chromium cast steels. Finally, the alloy ductility can be enhanced by additions of dopants such as B and Cr. Hence, additions of 0.03% B and 0.03%B-5% Cr combined with a heat treatment were implemented. As a result, the alloy ductility was significantly improved, where the strain of up to 5.3%, (B alone) or 15% (B-Cr) were obtained.
6
Content available Analysis of structure and abrasion resistance of the metal composite based on an intermetallic FeAl phase with VC and TiC precipitates
Kopyciński D., Guzik E., Gilewski R., Szczęsny A., Dorula J.
Archives of Foundry Engineering
|
2013
|
Vol. 13, iss. 3
51--54
EN
Metal alloys with matrix based on an Fe-Al system are generally considered materials for high-temperature applications. Their main advantages are compact crystallographic structure, long-range ordering and structural stability at high temperatures. These materials are based on an intermetallic phase of FeAl or Fe3Al, which is stable in the range from room temperature up to the melting point of 1240°C. Their application at high temperatures is also beneficial because of the low cost of production, very good resistance to oxidation and corrosion, and high mechanical strength. The casting alloy the structure of which includes the FeAl phase is, among others, high-aluminium cast iron. This study has been devoted to the determination of the effect of vanadium and titanium on the transformation of the high-aluminium cast iron structure into an in-situ FeAl-VC composite.
7
Content available The structure of high-quality aluminium cast iron
Kopyciński D., Guzik E., Szczęsny A., Gilewski R.
Archives of Foundry Engineering
|
2012
|
Vol. 12, iss. 1
53-56
EN
In this study presents the analyse of aluminium iron cast structure (as-cast condition) which are used in high temperature. While producing the casts of aluminium iron major influence has been preserve the structure of technological process parameters. The addition to Fe-C-Al alloy V, Ti, Cr leads to the improvement of functional and mechanical cast qualities. In this study, a method was investigated to eliminate the presence of undesirable Al4C3 phases in a aluminium cast iron structure and thus improve the production process. V and Ti additions in aluminium cast iron allows to development of FeAl - VC or TiC alloys. In particular, V or Ti contents above 5 wt.% were found to totally eliminate the presence of Al4C3. In addition, preliminary work indicates that the alloy with the FeAl - VC or TiC structure reveals high oxidation resistance. The introduction of 5 wt.% chromium to aluminium cast iron strengthened Al4C3 precipitate. Thus, the resultant alloy can be considered an intermetallic FeAl matrix strengthened by VC and TiC or modified Al4C3 reinforcements.
8
Content available remote Structure and properties of iron aluminide layers fabricated by the chemical vapour deposition on 316L steel
Sitek R., Kamiński J., Sallot P., Kurzydłowski K. J.
Materials Science Poland
|
2010
|
Vol. 28, No. 1
163--172
EN
The paper presents results of studies of structure and properties of the NiAl + FeAl type diffusion layers fabricated on 316L steel (00H17N14M2) by the chemical vapour deposition using aluminium chloride (AlCl3) in a hydrogen atmosphere as a carrier gas. The layers were examined using light and scanning electron microscopy. Chemical composition analyses were carried out by EDS and phase content was investigated by XRD. Corrosion resistance was tested using the potentiodynamic method in 0.5 M NaCl, and layer/structure adhesion was tested by the scratch test. The results obtained indicate that the 50 žm thick layers fabricated on the 316L steel substrate show very good adhesion combined with very good corrosion resistance.
9
Badania kluczowych charakterystyk mechanicznych stopów z układu FeAl
Jabłońska M.
Hutnik, Wiadomości Hutnicze
|
2009
|
Vol. 76, nr 8
586-590
PL
W artykule dokonano charakterystyki ważniejszych właściwości mechanicznych stopów konstrukcyjnych na osnowie faz międzymetalicznych Fe3 Al oraz FeAl. Stopy te ze względu na cenę i właściwości są konkurencyjne w stosunku do klasycznych stali odpornych na korozję i kwasoodpornych, dla których w przyszłości mogłyby stanowić zamienniki. Przedstawiono wyniki badań właściwości mechanicznych stopów Fe-28Al, Fe-28Al-5Cr, Fe-38Al (% at.) zawierających mikrododatki Mo, Zr, C, B, wyznaczonych w próbie jednoosiowego rozciągania w temperaturze pokojowej i podwyższonej oraz w próbie ściskania na gorąco. Wykonano badania faktograficzne próbek po rozciąganiu w celu określenia mechanizmu pękania. Obserwowano zwiększenie właściwości plastycznych wraz ze wzrostem temperatury testu. Ujawniono wpływ zawartości Al i dodatku stopowego (5 % at. Cr) na zmianę właściwości.
EN
The paper presents results of the investigation of the mechanical properties of the intermetallics alloys based on Fe3 Al and FeAl phases. These alloys are competitive for their cost and properties in comparison with stainless and acid resistance steels. In this work were analyzed the tensile properties of cast alloys Fe-28Al, Fe-28Al5Cr, Fe-38Al (% at.) contain microelements Mo, Zr, C, B. The tests were carried out at ambient and 600 °C temperature. Results of fractography after the tensile test at ambient and heighten temperature are presented too. Increase of ductile properties within increase the test temperature was observed. Disclose the influence of Al concentration and addition 5 % at. Cr on the strength characteristics change.
10
Content available remote Structure and some mechanical properties of Fe3Al-based cast alloys
Jabłońska M., Jasik A., Hanc A.
Archives of Metallurgy and Materials
|
2009
|
Vol. 54, iss. 3
731-739
EN
In the paper was studies the influence of chemical composition and temperature on the properties, microstructures, hardness and ordering process of intermetallics on the base closed to one of Fe3Al phase. The major problem restricting universal application of intermetallic phase base alloy from Fe-Al system is their low plasticity which leads to hampering their development as construction materials. The analysis were performed for two alloys i.e Fe28Al and Fe28Al-5Cr which were produced by casting and next were annealed for 8, 16 and 48 hours at 1000°C. Both alloys is closed to one of Fe3Al phase. Mechanical properties were measured by the uniaxial tensile test at room temperature and at 600°C. Some basic mechanical properties i.e. R0,2, Rm, A5, Z were determined. Were obtained increasing ductility with a increase the temperature test in air condition for both alloys. Structural examination was carried out using light microscopy and scanning electron microscopy. There observed that in Fe28Al alloy without Cr phases rich in Fe and Al, which can correspond to FeAlC0;5 were visible as well as phases rich in Zr. The precipitates rich in Cr and Zr were identified alloy with Cr which probably correspond to FeCr2 ZrC and Cr2Zr phases. The fractographs of destruction surfaces after tensile tests shown, that for both alloy at room temperature are brittleness and intergrannular. After the test at 600°C character of the fractures were changed (different). Were observed transgrannular cleavage for both alloys. The ordering process was analyzed by X-ray diffraction, M¨ossbauer spectroscopy. The studied alloys were prepared by melting in induction furnace under vacuum and next were gravitatively casted into cylindrical graphite moulds. After then samples were annealed at 1000°C for 8, 16 and 48 hours. Different behaviour of Fe-28Al and Fe-28Al-5Cr alloys after annealing were founded. Microstructures for both alloys was similar. Were indicated the presence of phases and precipitates in investigated alloys in the dendritic primary structure which wasn’t changes after the heat treatment process. Were observed the influence the time of annealing on the hardness alloys. Increasing time of annealing from 8h to 48h at 1000°C influenced on the increasing of hardness in Fe-28Al alloy and decreasing of hardness in Fe-28Al-5Cr alloy. X-ray diffraction method were obtained that the Fe3Al phase of DO3 type structure was stated only in the sample of Fe28Al alloy annealed for 48 hours. The FeAl phase appeared to be the main phase in the other samples. All the informations including a some of mechanical properties, analysis of microstructure, long range ordering during the heat treatment of studied alloys could be helpfully for technological processing this materials.
PL
W pracy przedstawiono wpływ składu chemicznego na właściwości, mikrostrukturę, twardość oraz proces porządkowania stopów na osnowie fazy Fe3Al. Badania prowadzono dla dwóch stopów: Fe28Al i Fe28Al-5Cr, które zostały wytworzone metodą odlewania próżniowego, a następnie poddane wyżarzaniu przez 8, 16 i 48 godzin w temperaturze 1000°C. Właściwosci mechaniczne obu materiałów wyznaczono na podstawie statycznej próby rozciągania w temperaturze pokojowej oraz w temperaturze 600°C. Wyznaczono podstawowe właściwości mechaniczne, takie jak: R0,2, Rm, A5, Z. Badania strukturalne przeprowadzono wykorzystując technikę mikroskopii świetlnej oraz skaningowej mikroskopii elektronowej. Zaobserwowano, iż w stopie Fe28Al bez dodatku Cr w strukturze tworzą się fazy bogate w Fe i Al, które scharakteryzowano jako FeAlC0,5. oraz fazy bogate w Zr jako jeden z mikrododatków. W stopie Fe28Al z 5% dodatkiem Cr ujawniono głównie tworzenie faz bogatych w Cr a takze w Zr, takich jak FeCr2 ZrC i Cr2Zr. Wykonane badania faktograficzne powierzchni zgładów powstałych po próbie rozciągania ujawniły, że charakter pękniecia stopów badanych w temperaturze pokojowej jest łamliwy i międzykrystaliczny. Po próbie przeprowadzonej w temp. 600°C przełomy miały charakter transkrystaliczny dla obu stopów. Proces porządkowania analizowano wykorzystując dyfrakcję rentgenowską, oraz spektroskopię efektu Mossbauer'a. Wykazano, że faza Fe3Al typu DO3 występuje tylko w próbce Fe28Al, która poddano wyżarzaniu przez 48 godzin. Fazę FeAl zaobserwowano w pozostałych próbkach.
11
Content available remote Structures and phases transitions of the alloys on the bases of Fe-Al intermetallic phases
Jabłońska M., Jasik A., Hanc A.
Archives of Materials Science and Engineering
|
2008
|
Vol. 29, nr 1
16-19
EN
Purpose: The paper presents study the results of investigations the influence of the chemical composition and thermal treatment on the microstructures and phases transitions of intermetallics from the Fe-Al system. Design/methodology/approach: Investigated alloys with 28, 38 and 42% at. Al were melted in vacuum induction furnace. Next stage of the preparing was gravity casting for cylindrical graphite moulds in the form of bars. The structure was analyzed after annealing at 1000°C for 24 and 48 h. The phases transitions were carried out by using a DTA method on the Setsys made by Setaram. Findings: The microstructure observations indicated the presence of phases and precipitates in all investigated alloys. In all of the investigated alloys, precipitation of phases present in the structure as a result of the introduction of alloying additions, such as Zr, Cr, Mo and C, is visible. transformations connected with both disorder-order transitions and the initial temperature at which a liquid phase occurred in the alloys had taken place during heating. Research limitations/implications: The investigations showed that the very important in production of intermetallics from Fe-Al system is casting and thermal treatment process. The important is knowledge about the phases transformations in this alloys which taking the informations about the melting points, order – disorder transition and their correlations with structure and in consequence the mechanical properties. Practical implications: The formation of phases and precipitates during the heat treatment in these alloys have not been known until now. This structures aspects are significantly affect the properties of intermetallics from the Fe-Al system. In correlation with temperatures of phases transition they could take the most important informations for technological processing. Originality/value: We needed more details about intermetallic from Fe-Al system for their development. This paper are the valid supplement for development knowledge of the iron aluminides.
12
Content available remote Ordering process of Fe28Al and Fe28Al5Cr alloys
Pająk L., Kansy J., Hanc A., Dercz G., Jabłońska M.
Archives of Materials Science and Engineering
|
2008
|
Vol. 30, nr 2
81-84
EN
Purpose: The comparison of ordering process in Fe28Al and Fe28Al5Cr alloys annealed for 8, 16 and 48 hours at 1000°C was performed. The composition of studied alloys is closed to one of Fe3Al phase. Design/methodology/approach: The studied alloys were melted in induction furnace under vacuum. Next the alloys were gravitatively casted into cylindrical graphite moulds. The alloy samples were annealed at 1000°C for 8, 16 and 48 hours. The ordering process was analyzed by X-ray diffraction,Mössbauerspectroscopy and positron annihilation methods. Findings: Different behaviour of Fe28Al and Fe28Al5Cr alloys during annealing for 8, 16 and 48 hours at 1000°C was found. The Fe3Al phase of DO3 type structure was stated only in the sample of Fe28Al alloy annealed for 48 hours. The FeAl phase appeared to be the main phase in the other samples. Research limitations/implications: The applied investigation methods appeared to be useful in the studies of long range ordering process. Application of Rietveld refinement method enabled the verification of qualitative phase analysis and the determination of lattice constant parameters. Relatively great grain sizes in studied samples made the exact determination of long range ordering parameters difficult. Practical implications: The information on the phase transformation during the heat treatment of alloys, including long range ordering, are of prime importance for technological processing. The structures with long range ordering significantly affect the properties of alloys with intermetallic phases. Originality/value: Good correlation between the results of X-ray diffraction, Mossbauer spectroscopy and positron annihilation methods were obtained. Addition of chromium made the long range ordering process slower.
13
Content available remote Mössbauer and structure studies on metallic powders from Fe-Al-X (X = Ni, Cu, Cr)
Hanc A., Dercz G., Pająk L., Frąckowiak J., Kansy J.
Archives of Materials Science and Engineering
|
2008
|
Vol. 31, nr 1
20-24
EN
Purpose: The Fe-Al-X and Fe-Al-Ni-X metallic powders produced by the self-decomposition process and then intensive grinding in an electro-magneto-mechanical mill with X = Fe, Ni, Cu, Cr additions was determined by applying the X-ray powder diffraction (XRD) and Mössbauer spectroscopy. Design/methodology/approach: The X-ray diffraction and Mössbauer spectroscopy were applied to identify the phase composition of the studied materials. Ordering process was analyzed by X-ray diffraction methods and Mössbauer spectroscopy. Findings: The effects of solute addition (X = Fe, Ni, Cu, Cr) in the investigated Fe-Al and Fe-Al-Ni metallic powders are presented and discussed. Good correlation between the results of X-ray diffraction and Mössbauer spectroscopy studies was obtained. Research limitations/implications: The Mössbauer spectroscopy appeared to be usefull in the identification of phase composition in studied materials. Application of Rietveld refinement method enabled the verification of this composition. Practical implications: The information on the phase transformation during the self-decomposition process and then intensive grinding in an electro-magneto-mechanical mill with additions are of prime importance for technological processing. Originality/value: All the phases that exist in the milled material contain high concentrations of aluminium (over 50 at. %) and have the ordered B2 structure. Alloying additions (Ni, Fe, Cu, Cr) and intensive high-energy grinding in the EMM mill modified the chemical and phase composition of the Fe-Al-X and Fe-Al-Ni-X samples.
14
Content available remote Hot rolling of intermetallics FeAl phase based alloys
Niewielski G., Kuc D., Schindler I., Bednarczyk I.
Archives of Materials Science and Engineering
|
2008
|
Vol. 29, nr 2
117-120
EN
Purpose: The one of major problem restricting universal employment of intermetallic phase base alloy is their low plasticity which leads to hampering their development as construction materials. The following work concentrates on possibilities to form through rolling process the alloys with various aluminium content. Design/methodology/approach: After casting and annealing, alloy specimens were subjected to axialsymmetric compression at temperatures ranging from 900 to 1200°C at 10 s-1 strain rates. In order to analyse the processes which take place during deformation, the specimens after deformation were intensely cooled with water. Structural examination was carried out using light microscopy. The process was conducted on the K -350 quarto rolling mill used for hot rolling of flat products. The process was conducted in some stages in at temperatures ranging from 1200-900°C: Findings: The research carried out enabled the understanding of the phenomena taking place during hot rolling of the investigated alloy. An alloy with 38%at. aluminium concentration can be plastically formed at a temperature of up to 900°C, which has been also confirmed in plastometric studies conducted in the form of hot compression tests. Research limitations/implications: Practical implications: The obtained sheets can be used as constructional elements working in complex stress fields, at a high temperature and corrosive environments Originality/value: The tests have shown that it is possible to form the investigated alloys through rolling processing only where shields are applied. Rolling of the alloys without shields led to the occurrence of a grid of cracks.
15
Content available remote Microstructure and mechanical properties of intermetallics on the base of Fe-Al alloy obtained by casting
Jabłońska M., Bernstock E., Jasik A.
Archives of Materials Science and Engineering
|
2007
|
Vol. 28, nr 10
625-628
EN
Purpose: The aim of this work is to study the results of investigations of chromium addition influence on a microstructure and tensile properties of intermetallics from the Fe-Al system based on Fe3Al phase. Design/methodology/approach: The alloys for investigations were prepared by induction melting and gravity casting. The microstructure was analyzed after homogenizing which was performed at 1000*C for 24 and 48 h. Mechanical properties have been analyzed by the tensile tests witch were carried out at ambient temperature. After that the fracture has been analyzed (sample after 48 h). Findings: As a result of microstructure observations of test alloys containing Cr and without Cr addition, the presence of phases and precipitates has been found. In both alloys Fe-28Al and Fe-28Al-5Cr the phases rich in Zr can be observed. Moreover in Fe-28Al-5Cr, phases rich in Cr are present mainly on grains boundaries, whereas Zr is present both on the borders and inside the grains. Carried out tensile tests and the results obtained indicate very low plasticity of both alloy without Cr addition and the alloy with the addition of 5% of Cr. Research limitations/implications: The investigations showed that the most important part of production of iron aluminides is casting process. One can not avoid the casting defects in the materials after casting. Therefore one should particularly pay attentin to melting and casting sequence. After the casting process one should the mechanism and the cause of the formation of phases and particles to get to know. The alternative for these materials so to subject produced in the aim of more far analyses to the plastic deformed. Practical implications: The reasons of formation of Zr, Cr and other phases in these alloys have not been exactly known until now. They can significantly affect the properties of intermetallics from the Fe-Al system. Originality/value: There have been disclosed the phases which are formed during casting and thermal processing in iron aluminides based on Fe3Al phase. They can significantly affect the properties of intermetallics from the Fe-Al system.
16
Content available Defect structure of Fe-Al and Fe-Al-X (X = Ni; Cu; Cr) metallic powders obtained by the self-decomposition method
Hanc A., Frąckowiak J.
Nukleonika
|
2004
|
Vol. 49,suppl.3
7-11
EN
In the present work, the Fe-Al-X (X = Cu; Ni; Cr) metallic powders produced by the self-decomposition method of the Fe-Al doped alloys were examined by Mössbauer spectroscopy. The concentration of the Fe vacancies and the Fe atoms substituting Al (Fe-AS) was determined from the intensities of the sub-spectra in the Mössbauer analysis connected with distinct Fe environments. The results have shown that nickel and copper cause an increase of vacancy concentrations in comparison with the values found for Fe-Al metallic powders, whereas chromium decreases vacancy concentrations causing a significant increase of anti-site atoms Fe-AS concentration.
17
Content available remote The structure and tribological properties of Fe-Al based intermetalics alloys
Komorek Z., Bojar Z., Czujko T.
International Journal of Applied Mechanics and Engineering
|
2002
|
Vol. 7, Spec. is
365-368
EN
The main purpose of presented work was to describe basic tribological properties of Fe-Al intermetalics depending on their structure and selected mechanical properties. Two different kind of intermetallic alloys with predominant contents of Fe3Al or FeAl intermetallic phases, in as-cast, homogenized or softened conditions were investigated by microstructure and chemical analysis, microhardness measurement, compression and impact testing. Alloys with significantly different condition of structure were tribologically tested using pin-on disc method and the relationship between properties and abrasive wear resistance of Fe-Al intermetallics in bulk form was discussed.
18
Structural and functional intermetallics - an overview.
Varin R.A.
Inżynieria Materiałowa
|
2001
|
R. XXII, nr 1
11-18
EN
This overview presents the current status of the research and development of both structural and functional intermetallics. On the one hand, the discussion is focused on commercialization and existing industrial applications of intermetallics. Within this frame the applications of titanium aluminides (TiAl) for turbocharger rotors and exhaust valves in automotive industry are being discussed. Advances in the application of TiAl alloys for the next generation of turbine blades in aerospace/aircraft segment are presented. The entire spectrum of nickel and iron aluminide alloys developed commercially by the Oak Ridge National Laboratory (USA) and the examples of their application in various segments of industry are thoroughly discussed. Some inroads made in the application of directionally solidified (DS) multiphase niobum silicides (Nb3Si + Nb5Si3) insitu intermetallic composites with the goal of pushing the service temperature envelope of turbine blades to ~ 1200-1300 degrees centigrade are also discussed. On the other hand, various topics in basic or curiosity driven research of titanium aluminides and trialuminides, iron aluminides and high temperature structural silicides are discussed. Some very recent findings on the improvements in fracture toughness and strength of titanium trialuminides and magnetic behaviour of unconventionally cold-worked iron aluminides are highlighted. The topic of functional intermetallics is limited to the systems most suitable for hydrogen storage applications. A perspective on the directions of future research and development of intermetallics is also provided.
PL
Praca przedstawia w sposób przeglądowy aktualny stan badań i rozwoju konstrukcyjnych oraz funkcjonalnych stopów na osnowie faz międzymetalicznych. Z jednej strony dyskusja skupia się na komercjalizacji i dotychczasowych zastosowaniach faz międzymetalicznych w przemyśle. W obrębie tych zagadnień omawiane są aplikacje stopów na osnowie fazy TiAl na odlewy wirników układu turbodoładowania oraz zawory wylotowe dla przemysłu motoryzacyjnego. W pracy przedstawiono również zalety zastosowania stopów TiAl na nowej generacji łopatki turbin w przemyśle kosmicznym i lotniczym. Omówiono szerokie spektrum niklowych i żelazowych aluminidków komercyjnie rozwijanych przez Oak Ridge National Laboratory (USA), a także zaprezentowano przykłady ich zastosowania w przemyśle. Dyskutowane są zastosowania wielofazowych, insitu kompozytów Nb3Si + Nb5Si3 otrzymywanych za pomocą krystalizacji kierunkowej, które pozwalają podnieść temperaturę pracy łopatek turbin do ~1200-1300 stopni Celsjusza. Z drugiej strony w artykule poruszane są różne zagadnienia natury podstawowej i kuriozalnej, które są siłą napędową badań aluminidków tytanowych, żelazowych, trójskładnikowych na osnowie tytanu i wysokotemperaturowych faz międzymetalicznych z udziałem krzemu. W pracy przedstawiono wyniki ostatnich badań dotyczących poprawy odporności na kruche pękanie i wytrzymałości trójskładnikowych aluminidków tytanowych, a także opisano zachowanie magnetyczne aluminidków żelazowych poddanych zgniotowi na zimno. Zagadnienia z obszaru funkcjonalnych faz międzymetalicznych ograniczono do układów odpowiednich dla zastosowań do magazynowania wodoru. W artykule przedstawiono również perspektywiczne kierunki badań i rozwoju stopów na osnowie faz międzymetalicznych.
19
Wysokotemperaturowa synteza SHS kompozytowych proszków zawierających aluminidki żelaza i tytanu oraz tlenek glinu - warunki syntezy i struktura proszków.
Formanek B., Maciejny A., Szymański K., Szala J., Pająk L., Przeliborz R.
Inżynieria Materiałowa
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1999
|
R. XX, nr 3-4
150-158
PL
Przedstawiono technologiczną koncepcję wytwarzania kompozytowych proszków zawierających fazy międzymetaliczne i tlenki przeznaczone do natryskiwania cieplnego powłok lub spiekania. Zcharakteryzowano metodę samorozwijającej się syntezy wysokotemperaturowej SHS wytwarzania spieków zawierających fazy międzymetaliczne z układu Fe-Ti-Al i tlenek glinu. Określono procedurę postępowania technologicznego ujmującego przygotowanie materiałów wyjściowych do syntezy, parametry syntezy, rozdrabniania spieków, przygotowania i klasyfikacji proszków do natryskiwania cieplnego. Na podstawie wyników termicznej analizy różnicowej wskazano charakterystyczne temperatury dla syntezy mieszanin wyjściowych zawierających rudy tytanu i aluminium. Określono wpływ skłądu chemicznego i procentowej zawartości reduktora, wielkości ziarn substratów na intensywność zachodzących reakcji syntezy. Przeprowadzono analizę termiczną procesu. Przedstawiono strukturę spieków, określono skład chemiczny i fazowy wydzieleń metalicznych w spiekach. Korekta parametrów procesu SHS pozwoliła otrzymać spieki o jednolitej budowie. Określono skład fazowy i morfologię proszków przeznaczonych do natryskiwania cieplnego powłok.
EN
Technological conception of manufacturing of composite powders containing intermetallic phases and oxides for thermal spraying or sintering. A method of the self-propagating high temperature synthesis (SHS) of forming sinters with intermetallic phases from the Fe-Ti-Al system and the aluminium oxide was characterised. A procedure of technological treatment including preparation of initial materials for synthesis, synthesis parameters, milling of sinters, preparing and classification of powders for thermal spraying was determined. On the basis of the thermal differential analysis results characteristic temperatures for synthesis of initial mixtures with titanium and aluminium ores were established. An influence of the chemical composition and percentage of the reducer, the grain size of substrates on intensity of occuring reactions of the synthesis was determined. A thermal analysis of the process was performed. The structure of sinters was presented, the phase and chemical composition of metallic precipitates in the sinters was determined. The correction of the SHS process parameters enabled to obtain sinters with uniform structure. The chemical composition and morphology of powders for thermal spraying of coatings were determined.
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