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Photoelectrochemical (PEC) water splitting requires stable, efficient, and cost‐effective photoelectrodes to enable future large‐scale solar hydrogen production. Ultrathin hematite‐hercynite photoanodes that meet all these criteria in an excellent way is presented here. Hematite‐hercynite photoelectrodes are synthesized in a self‐forming manner by thermal oxidation of iron–aluminum alloy films and characterized with regard to water splitting applications. Photoanodes fabricated from 17 wt.% Al at 493 °C for 8 h and 685 °C for 5 min exhibit, for instance, a photocurrent density of 1.24 and 1.53 mA cm−2 at 1.23 V versus RHE, respectively, as well as superior light absorption in the visible range of the solar spectrum. The PEC performance improvement in comparison to pure hematite thin film electrodes is first achieved by adjusting the aluminum concentration with an optimum range of 12–17 wt.% and second by optimizing the annealing conditions. The resulting photocurrent densities are about a factor of three higher than those obtained from electrodes synthesized from pure iron thin films using the same synthesis conditions. Finally, it is shown that ultrathin hematite‐hercynite photoelectrodes enable even unassisted solar water splitting in a NaOH (1 m) electrolyte with a maximum solar‐to‐hydrogen conversion efficiency of 0.78%. [ABSTRACT FROM AUTHOR]

A recently published study of high temperature nitridation of iron chromium aluminum alloys (FeCrAl) at 900°C in N2–H2 has redundantly shown the formation of locally confined corrosion pockets reaching several microns into the alloy. These nitrided pockets form underneath chromia islands laterally surrounded by the otherwise protective alumina scale. Chromia renders a nitrogen‐permeable defect under the given conditions and the presence of aluminum in the alloy. In light of these findings on FeCrAl, a focused ion beam–scanning electron microscope tomography study has been undertaken on an equally nitrided FeNiCrAl sample to characterize its nitridation corrosion features chemically and morphologically. The alloy is strengthened by a high number of chromium carbide precipitates, which are also preferential chromia formation sites. Besides the confirmation of the complete encapsulation of the corrosion pocket from the alloy by a closed and dense aluminum nitride rim, very large voids have been found in the said pockets. Furthermore, metallic particles comprising nickel and iron are deposited on top of the outer oxide scale above such void regions. [ABSTRACT FROM AUTHOR]

Fe‐Al alloying is a matter of interest because of its technological importance and many applications. Different growth conditions may lead to different results, ie, formation of various phases. These phases may be magnetic or nonmagnetic in nature. Cosputtering of Fe and Al with magnetron‐sputtering setup provides us with a good option of alloying and to study the various phase formations. As, yet now researchers studied the alloying through cosputtering process only in oxygen environment, so a study in nonreactive environment was inevitable and interesting. Therefore, the authors went for Fe‐Al thin‐film synthesis using the magnetron sputtering in argon environment. Hence, this paper discusses the Fe and Al alloy formation in argon environment and annealed the samples at different temperatures for different time durations so as to allow various phase formations. The samples were characterized with grazing incidence X‐ray diffraction (GIXRD), grazing incidence X‐ray reflectivity (GIXRR), magneto‐optical Kerr effect (MOKE), and atomic force microscopy (AFM) techniques so as to study structural, morphological, and magnetic properties. The results confirm that cosputtering provides better chances of alloying and also supports formation of various stable phases in comparison with other available techniques. [ABSTRACT FROM AUTHOR]

High‐pressure torsion at room temperature followed by two processing routes, either 1) annealing at 200 °C for 8 h or 2) elevated temperature (200 °C) high‐pressure torsion, are employed to obtain simultaneous increase in mechanical strength and electrical conductivity of Al–2 wt%Fe. The comparative study of microstructure, particle distribution, mechanical properties, and electrical conductivity for both processing routes gives the optimal combination of high mechanical strength and high electrical conductivity in Al–2Fe alloy. It is shown that while the mechanical strength is approximately the same for both processing routes (>320 MPa), high‐pressure torsion at elevated temperature results in higher conductivity (≥52% IACS) due to reduction of Fe solute atom concentration in Al matrix compared to annealing treatment. High‐pressure torsion at 200 °C has been demonstrated as a new and effective way for obtaining combination of high mechanical strength and electrical conductivity in Al–Fe alloys. [ABSTRACT FROM AUTHOR]

Al-Fe alloys, with large amounts of sphere-like structures, few plate-like structures, and little needle-like structures of micron scale second phase have been successfully prepared via a new type of solid-liquid mixture approach combined with plasma arc heating (PAH). The authors have obtained Al-Fe alloys with iron content of 0-15%, which is of extremely significance that thermal plasma jet (TPJ) breaks through the limitation of low iron content in Al-Fe alloys. Microstructures characterization indicates that not only the microstructures of Al-Fe alloys are refined, but also the morphologies are optimized. Meanwhile, sharp corners of iron powders are rounded off and impurities are removed under the action of PAH, which is important for improving mechanical property of Al-Fe alloys. And then, the effects of various parameters including PAH, iron content, and melt temperature on the microstructures and mechanical performance are systematically investigated. The possible influence mechanisms of parameters are investigated and put forward, and appropriate parameters have been obtained during the processing of Al-Fe alloys via TPJ. [ABSTRACT FROM AUTHOR]

A new model for fast calculation of texture evolution during the hot rolling of low-alloyed aluminum sheets with iron addition in continuous mill is developed. Experiments are carried out for developing a relationship between accumulated strain and deformation texture components. A special fast analytic algorithm is used for the calculation of strip temperature and accumulated strain. For the recrystallization texture components calculation, Vatne's approach is used. For its successful realization, some additional experiments and model improvement are also carried out. These experiments help to establish the rate of grain border movements and the amount of second-phase particles with size critical for recrystallization nucleation. The developed model is used for calculation of the texture evolution during 8011 alloy hot rolling in an industrial continuous mill. The results enable us to choose the correct temperature and deformation parameters that allow us to obtain the necessary texture composition. In addition, the approach can be also adjusted for other aluminum alloys after some additional improvements. Generally, the method can be applied to steels, but in this case some empirical formulations for deformation and recrystallization textures formation used in calculations should be revised. [ABSTRACT FROM AUTHOR]

Fe-Al alloys in the aluminium range of 55-65 at.% exhibit a lamellar microstructure of B2-ordered FeAl and triclinic FeAl2, which is caused by a eutectoid decomposition of the high-temperature Fe5Al8 phase, the so-called ϵ phase. The orientation relationship of FeAl and FeAl2 has previously been studied by Bastin et al. [ J. Cryst. Growth (1978), 43, 745] and Hirata et al. [ Philos. Mag. Lett. (2008), 88, 491]. Since both results are based on different crystallographic data regarding FeAl2, the data are re-evaluated with respect to a recent re-determination of the FeAl2 phase provided by Chumak et al. [ Acta Cryst. (2010), C 66, i87]. It is found that both orientation relationships match subsequent to a rotation operation of 180° about a ⟨112⟩ crystallographic axis of FeAl or by applying the inversion symmetry of the FeAl2 crystal structure as suggested by the Chumak data set. Experimental evidence for the validity of the previously determined orientation relationships was found in as-cast fully lamellar material (random texture) as well as directionally solidified material (∼⟨110⟩FeAl || solidification direction) by means of orientation imaging microscopy and global texture measurements. In addition, a preferential interface between FeAl and FeAl2 was identified by means of trace analyses using cross sectioning with a focused ion beam. On the basis of these habit planes the orientation relationship between the two phases can be described by (01)FeAl || (114) and [111]FeAl || [10]. There is no evidence for twinning within FeAl lamellae or alternating orientations of FeAl lamellae. Based on the determined orientation and interface data, an atomistic model of the structure relationship of Fe5Al8, FeAl and FeAl2 in the vicinity of the eutectoid decomposition is derived. This model is analysed with respect to the strain which has to be accommodated at the interface of FeAl and FeAl2. [ABSTRACT FROM AUTHOR]

Fe-Al alloys in the aluminium range of 55-65 at.% exhibit a lamellar microstructure of B2-ordered FeAl and triclinic FeAl2, which is caused by a eutectoid decomposition of the high-temperature Fe5Al8 phase, the so-called ϵ phase. The orientation relationship of FeAl and FeAl2 has previously been studied by Bastin et al. [ J. Cryst. Growth (1978), 43, 745] and Hirata et al. [ Philos. Mag. Lett. (2008), 88, 491]. Since both results are based on different crystallographic data regarding FeAl2, the data are re-evaluated with respect to a recent re-determination of the FeAl2 phase provided by Chumak et al. [ Acta Cryst. (2010), C 66, i87]. It is found that both orientation relationships match subsequent to a rotation operation of 180° about a ⟨112⟩ crystallographic axis of FeAl or by applying the inversion symmetry of the FeAl2 crystal structure as suggested by the Chumak data set. Experimental evidence for the validity of the previously determined orientation relationships was found in as-cast fully lamellar material (random texture) as well as directionally solidified material (∼⟨110⟩FeAl || solidification direction) by means of orientation imaging microscopy and global texture measurements. In addition, a preferential interface between FeAl and FeAl2 was identified by means of trace analyses using cross sectioning with a focused ion beam. On the basis of these habit planes the orientation relationship between the two phases can be described by (01)FeAl || (114) and [111]FeAl || [10]. There is no evidence for twinning within FeAl lamellae or alternating orientations of FeAl lamellae. Based on the determined orientation and interface data, an atomistic model of the structure relationship of Fe5Al8, FeAl and FeAl2 in the vicinity of the eutectoid decomposition is derived. This model is analysed with respect to the strain which has to be accommodated at the interface of FeAl and FeAl2. [ABSTRACT FROM AUTHOR]

Armored vehicles are primarily designed to provide protection against blast and ballistic events and secondly to improve the manoevrability in battlefield. The manoevrability can be materialized by weight reduction of the vehicles, which also leads to the decrease in operating cost. To obtain improved performance without compromising blast and ballistic properties, explosion bulge testing was adpoted in this work to strengthening a austenitic twinning-induced plasticity (TWIP) steel. The pre-blast technique significanly reduced the grain size of the material which increased the hardness. The electron backscattered diffraction (EBSD) was conducted to study the microstructure and the dominant deformation mechanism was found to be dislocation slips. As a result, it was found that soft materials like TWIP steel lost a minimal toughness but showed strongly work-hardened after blasts. Based on this result, it is possible that the lifecycle of armor vehicles could be significantly expanded and the repair cost could be greatly reduced. [ABSTRACT FROM AUTHOR]

Abstracts are presented on topics including stress generation and relaxation in aluminum oxides, phase transformation of aluminum oxide scale on iron-aluminum alloys, and the steam oxidation behavior of cobalt base alloy 25.

The effect of oxygen partial pressure on the phase transformation of Al2O3 scale on various Fe-Al alloys with and without very thin (∼100 nm) Fe coating was investigated. Fe-coating on Fe-Al alloys can effectively suppress metastable Al2O3 formation, but little effect was observed when the samples were oxidized in a low partial pressure of oxygen. Under the low ${\rm P}_{{\rm O}_{{\rm 2}} } $ atmosphere, metastable to stable α-Al2O3 scale phase transformation on both Fe-coated and non-coated Fe-Al alloys was significantly delayed. The lattice spacing of α-Al2O3 scale formed in air decreased with increasing alloy Al content. Further decrease in the lattice spacing of α-Al2O3 scale was observed when the alloy was oxidized in low ${\rm P}_{{\rm O}_{{\rm 2}} } $. The results obtained clearly indicated that the formation of Fe2O3 or Fe3+ in metastable Al2O3 accelerated the metastable to stable α-Al2O3 scale transformation. [ABSTRACT FROM AUTHOR]

Three-dimensional electron diffraction intensity data have been collected for the metastable ahoy phase Al[subm]Fe by a precession technique. The structure model has been derived by Patterson and Fourier calculations and by the direct method using either maximum entropy and likelihood or the tangent formula: both were based on the kinematical scattering approximation. Energy-filtered convergent-beam profiles for reflections along two systematic rows h00 and hbo were used to determine the corresponding structure factors: these were introduced in a dynamical scattering correction procedure, for all hk0 structure factors. The tetragonal Al[subm]Fe structure (a = 8.84, c = 21.6 Å, space group 142m) with Al Al and 20 Fe atoms can be described by ten-coordinated Fe or by a distorted CsCltype network with vacancies. [ABSTRACT FROM AUTHOR]

Single crystals of Mg-substituted CeFe2Al8-type intermetallics LnFe2MgxAl8-x (Ln: La-Nd, Sm; x ≤ 1) are grown by reaction of Fe and Ln in a 1:1 Mg/Al reactive flux (steel capsules in evacuated silica tubes, 950 °C, 5 h; controlled cooling). [ABSTRACT FROM AUTHOR]

The title compounds (IV) are obtained by an efficient and environmentally benign condensation of various aldehydes, ethylacetoacetate, and urea/thiourea using Fe-Al clay as catalyst. [ABSTRACT FROM AUTHOR]