Are there stable long-range ordered Fe(1-x)Cr(x) compounds?

The heat of formation of Fe-Cr alloys undergoes an anomalous change of sign at small Cr concentrations. This observation raises the question whether there are intermetallic phases present in this composition range. Here we report the discovery of several long-range ordered structures that represent ground state phases at zero Kelvin. In particular we have identified a structure at 3.7% Cr with an embedding energy which is 49 meV/Cr atom below the solid solution. This implies there is an effective long-range attractive interaction between Cr atoms. We propose that the structures found in this study complete the low temperature-low Cr region of the phase diagram.Comment: 3 pages, 2 figure

The Effect of Electronic Structure on the Phases Present in High Entropy Alloys

Multicomponent systems, termed High Entropy Alloys (HEAs), with predominantly single solid solution phases are a current area of focus in alloy development. Although different empirical rules have been introduced to understand phase formation and determine what the dominant phases may be in these systems, experimental investigation has revealed that in many cases their structure is not a single solid solution phase, and that the rules may not accurately distinguish the stability of the phase boundaries. Here, a combined modelling and experimental approach that looks into the electronic structure is proposed to improve accuracy of the predictions of the majority phase. To do this, the Rigid Band model is generalised for magnetic systems in prediction of the majority phase most likely to be found. Good agreement is found when the predictions are confronted with data from experiments, including a new magnetic HEA system (CoFeNiV). This also includes predicting the structural transition with varying levels of constituent elements, as a function of the valence electron concentration, n, obtained from the integrated spin-polarised density of states. This method is suitable as a new predictive technique to identify compositions for further screening, in particular for magnetic HEAs

Иноязычная коммуникативная компетенция современного преподавателя технического вуза

В статье рассматриваются организационно-педагогические и методические условия формирования иноязычной коммуникативной компетенции преподавателя технического вуза на примере реализации программы повышения квалификации "Формирование профессиональной дидактической компетенции средствами английского языка". Иностранный язык становится инструментом для выполнения профессиональной деятельности современного преподавателя технического вуза

Bond-order potential for simulations of extended defects in tungsten

We present a bond-order potential (BOP) for the bcc transition metal tungsten. The bond-order potentials are a real-space semiempirical scheme for the description of interatomic interactions based on the tight-binding approximation. In the hierarchy of atomic-scale-modeling methods the BOPs thus provide a direct bridge between electronic-structure and atomistic techniques. Two variants of the BOP were constructed and extensively tested against accurate first-principles methods in order to assess the potentials\u27 reliability and applicability. A comparison of the BOP with a central-force potential is used to demonstrate that a correct description of directional mixed covalent and metallic bonds is crucial for a successful and fully transferable model. The potentials are applied in studies of low-index surfaces, symmetrical tilt grain boundaries, and dislocations

Seasonal dynamics of native and invasive Halophila stipulacea populations—A case study from the northern Gulf of Aqaba and the eastern Mediterranean Sea

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Gamma ray production in inelastic scattering of neutrons produced by cosmic muons in 56^{56}Fe

We report on the study of the intensities of several gamma lines emitted after the inelastic scattering of neutrons in $^{56}$Fe. Neutrons were produced by cosmic muons passing the 20t massive iron cube placed at the Earth's surface and used as a passive shield for the HPGe detector. Relative intensities of detected gamma lines are compared with the results collected in the same iron shield by the use of $^{252}$Cf neutrons. Assessment against the published data from neutron scattering experiments at energies up to 14 MeV is also provided