Microstructural evolution and room-temperature mechanical properties of as-cast and heat-treated Fe50Al50−nNbn alloys (n=1, 3, 5, 7, and 9at%)

Yildirim, Mehmet; Akdeniz, M. Vedat; Mekhrabov, Amdulla O.

doi:10.1016/j.msea.2016.03.128

Cited by 22 publications

(7 citation statements)

References 51 publications

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“…At a temperature of 650 °C and stresses higher than 200 MPa, the 5% niobium alloy has the best creep resistance. In this regard, our results fully agree with the findings of Yildirim et al [18], whose tests were conducted at room temperature and strain rate 10 −4 s −1 . They observed a similar weakening of the heat-treated eutectic alloy and attributed lower compressive strength and fracture strain of this alloy to the absence of softer Fe-Al-based primary dendrites.…”

supporting

confidence: 92%

“…% throughout this paper) [6][7][8][9][10] and alloys based on ordered compounds of Fe 3 Al [8,9,[11][12][13][14][15][16][17]. Recently, the influence of niobium additions to FeAl (Fe-(50−x)% Al-x% Nb, x = 1, 3, 5, 7, 9) [18], i.e., up to the eutectic through between FeAl and C14 Laves phase on room-temperature mechanical properties were studied. It was shown that the eutectic alloy with 9% Nb exhibited the lowest compressive strength among the heat-treated alloys.…”

Section: Introductionmentioning

confidence: 99%

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The Influence of Niobium Additions on Creep Resistance of Fe-27 at. % Al Alloys

Dobeš

Dymáček

Friák

2019

Metals

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Results of creep tests of two Fe-27 at. % Al-based alloys with additions of 2.7 and 4.8 at. % of niobium conducted in the temperature range from 650 °C to 900 °C in the authors’ laboratory are presented. The purpose of the study is to supplement previous work on Fe-Al-Nb alloys to obtain a more complete overview of creep properties from the dilute alloy with 1% of Nb up to the eutectic alloy with 10% of niobium. At higher temperatures and lower stresses, the creep resistance of the 10% niobium alloy is better than that of the lower niobium alloys. On the other hand, the eutectic alloy loses its preference at lower temperatures and higher deformation rates. This phenomenon is similar to that reported by Yildirim et al. for Fe-50 at. % Al-based alloys and is probably associated with an increased stress sensitivity of the eutectic alloy.

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confidence: 92%

Section: Introductionmentioning

confidence: 99%

The Influence of Niobium Additions on Creep Resistance of Fe-27 at. % Al Alloys

Dobeš

Dymáček

Friák

2019

Metals

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“…Specifically, strengthening by intermetallic Laves phases is one of the concepts leading to improving the high-temperature mechanical properties of iron aluminides [1,5,9,10]. The addition of alloying elements (A), including Nb [11,12], Ta [13,14], Ti [15], or Zr [16], leads to the formation of a Laves phase in a thermodynamic equilibrium with the iron aluminide matrix. The resulting C14 A(Fe, Al) 2 Laves phases precipitate as fine incoherent particles from the supersaturated aluminide matrix phase or form a eutectic mixture depending on the alloying quantity [17].…”

Section: Introductionmentioning

confidence: 99%

Laser Powder Bed Fusion Additive Manufacturing of Fe3Al-1.5Ta Iron Aluminide with Strengthening Laves Phase

Emdadi

Bolz

Buhl

et al. 2022

Metals

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Advanced aluminides strengthened with incoherent Laves phase precipitates are promising lightweight and creep-resistant alternatives for high-alloy steels and superalloys for high-temperature critical components up to 750 °C service temperature. A significant issue with manufacturing these aluminides with conventional casting is the strong coarsening tendency of the Laves phase precipitates at elevated temperatures, leading to a significant strength reduction. In this context, the short lifetime of the melt pool in additive manufacturing and its fast solidification and cooling rates promise to consolidate these aluminides with homogeneously distributed fine Laves phase particles without coarsening. The main scientific objective of this work is to exploit the unique characteristics of the laser powder bed fusion (L-PBF) additive manufacturing (AM) process to print dense and crack-free bulk Fe3Al-1.5Ta samples containing uniformly distributed (Fe, Al)2Ta Laves phase precipitates. The Fe-25Al-2Ta (at.%) alloy was selected for this work since its creep resistance at 650 °C surpasses the one of the P92 martensitic–ferritic steel (one of the most creep-resistant alloys developed for steam turbine applications). Fundamentals on process–microstructure relationships governing the L-PBF-fabricated builds are provided by a detailed microstructural characterization using X-ray diffractometer (XRD) and ultra-high-resolution scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX) and high-resolution electron backscatter diffraction (EBSD) detectors. Orientation imaging microscopy (OIM) and grain reference orientation deviation (GROD) maps were applied to measure texture and visualize substructures within the grains. The mechanism of voids formation, morphology, and volume fraction as a function of the input energy density was identified. The melting and solidification dynamics led to microstructures with large columnar grains, porosity, and periodic cracks during the printing process. Processing samples at the building temperatures below the brittle-to-ductile transition temperature, BDTT (750 °C), often caused severe macrocracking and delamination. Crack-free samples with densities higher than 99%, some approaching 99.5%, were fabricated from pre-alloyed gas-atomized powders with a combination of high laser power (250–300 W), slow-to-medium scanning speed (500–1000 mm/s), and 800 °C build plate preheating using a 67° rotation scanning strategy. The morphology of the pores in the volume of the samples indicated a relatively sharp transition from spherical geometry for scanning speeds up to 1000 mm/s to crack-like pores for higher values. The ultra-fast cooling during the L-PBF process suppressed D03 Fe3Al-ordering. The Fe3Al-1.5Ta builds were characterized by B2 FeAl-type order clusters dispersed within a disordered A2 α-(Fe, Al) matrix. Additionally, the (Fe, Al)2Ta Laves phase (C14–P63/mmc) was predominantly formed at the matrix phase grain boundaries and frequently dispersed within the grains. The quantitative EDX analysis of the matrix gave 77.6–77.9 at.% Fe, 21.4–21.7 at.% Al, and 0.6–0.8 at.% Ta, while the composition of the Laves phase was 66.3–67.8 at.% Fe, 8.7–9.8 at.% Al, and 22.4–24.9 at.% Ta, indicating that the Laves phase is considerably enriched in Ta with respect to the matrix. The L-PBF-fabricated alloys were characterized by coarse, columnar grains which grow epitaxially from the substrate, were several m in width, and extended across several layers along the building direction. The grains exhibited a relatively strong microtexture close to <0 0 1> with respect to the building direction. The L-PBF builds showed a bulk hardness value comparable to the as-cast and spark plasma-sintered counterparts. A negligible variation of the hardness across the build height was observed. Within the framework of this study, we demonstrated that the porosity and cracking issues could be resolved mainly by controlling the process parameters and preheating the build platform above the BDTT. Nevertheless, alloy modifications and/or post-manufacturing processing are required for microstructure refinement.

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“…This higher value of melting temperature and elastic modulus has limited their biomedical applications. However, by the addition of third alloying element, their properties can be improved significantly which makes them suitable for biomedical applications [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Archives of Metallurgy and Materials

Hussain,

Ziya,

Atiq

et al. 2020

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The statistical-thermodynamic theory of ordering and electronic theory of ordering in the pseudo-potential approximation was used to study the influence of ternary addition of some transition metals on the atomic ordering behavior of Co 0.5 (Ti 1-x m x ) 0.5 alloys with m = Fe, Pt, re, V, Cr, mn, Ni, Cu, Zn, Zr, Ag, Hf or Au up to a concentration of 1 at.%. The partial ordering energies, order-disorder phase transformation temperatures and partial short range order parameters have been calculated for these alloys. The analysis shows that the impurity elements in Co 0.5 (Ti 1-x m x ) 0.5 alloys can be divided into two main groups on the basis of lattice site occupancy i.e. m = V, Cr, mn, Cu, Zn, Zr, Ag, Hf and Au mainly substitute for Co sublattice sites whereas m = Fe, Ni, Pt or re mainly substitute for Ti sublattice sites. Further, the order-disorder transformation temperatures were found to either increase or remain nearly unchanged by the addition of ternary impurities in the CoTi alloy depending on the absolute value of the partial ordering energies. Alloys of Ti with V, Cr, mn, Cu, Zn, Zr, Ag, Hf or Au in place of Co and alloys of Co with Fe, Ni, Pt or re in place of Ti can be predicted for future. The results of the present analysis are in good agreement with the available experimental data on these alloys.

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Microstructural evolution and room-temperature mechanical properties of as-cast and heat-treated Fe50Al50−nNbn alloys (n=1, 3, 5, 7, and 9at%)

Cited by 22 publications

References 51 publications

The Influence of Niobium Additions on Creep Resistance of Fe-27 at. % Al Alloys

The Influence of Niobium Additions on Creep Resistance of Fe-27 at. % Al Alloys

Laser Powder Bed Fusion Additive Manufacturing of Fe3Al-1.5Ta Iron Aluminide with Strengthening Laves Phase

Archives of Metallurgy and Materials

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