A complete thermodynamic description of the Bi–Mg–Sn ternary system was obtained by means of the CALPHAD (CALculation of PHAse Diagram) technique. The solution phases, Rhomb, Bct_A5 and Hcp_A3, are ...modeled with Redlich–Kister equation. The associate model has been used to describe the liquid phase with the constituents of the species Bi, Bi2Mg3, Mg, Mg2Sn and Sn. The non-stoichiometric compounds Mg2Sn and α-Bi2Mg3 as well as its high temperature variant β-Bi2Mg3 were described by the sublattice models (Bi,Mg)2(Bi,Sn)1, (Bi,Sn,Va)2Mg3 and (Bi,Sn)1(Bi,Sn,Va)3Mg6, respectively. The Bi–Mg–Sn ternary system has been modeled thermodynamically for the first time and the calculated phase equilibrium relations and thermochemical properties are consistent with the experimental results available in literatures.
The thermodynamic assessment of the BiaRb system was carried out by using the CALculation of PHAse Diagrams (CALPHAD) method on the basis of experimental thermodynamic data and phase equilibrium ...measurements. Considering the short range ordering behavior of the liquid phase, the associate model was used with the constituent species Bi, BiRb, BiRb3 and Rb. All the intermetallic compounds, Bi2Rb, Bi2Rb3, Bi4Rb5, I--BiRb3 and I2-BiRb3, with no experimentally determined solubility ranges were treated as stoichiometric compounds. The solution phases, the Bi-rich terminal phase Rhombohedral_A7 and the Rb-rich terminal phase BCC_A2, were treated as the pure substances since the extremely small solubility of the second alloying element in each of these phases. A set of self-consistent thermodynamic parameters was obtained for the BiaRb system and the CALPHAD results can reproduce the experimental thermochemical properties and the measured phase equilibrium relations well.
With the consideration of the existence of the metastable miscibility gaps, the thermodynamic parameters of the Mg-based solid solution have been assessed for the Mg–Zn and Mg–Nd systems. The new ...semi-empirical equation proposed by Kaptay was used to describe the interaction parameters between components to prevent the appearance of the artificial miscibility gap at high temperature. The obtained thermodynamic descriptions can reproduce the metastable miscibility gaps and the spinodal decomposition curves in the Mg–Zn and Mg–Nd systems. The driving force calculation can explain well the precipitation of the second hcp_A3 phase (Guinier–Preston zones) in the primary Mg-based hcp_A3 matrix, as well as the decomposition sequence following a quench from a single-phase supersaturated solid solution to a two-phase regime. The miscibility gap of the Mg-based phase in the Mg–Zn–Nd ternary system was predicted on the basis of the descriptions of the Mg–Zn and Mg–Nd binary systems without consideration of the three-component interactions.
The criterion for coherent equilibria is investigated. The expressions of driving force considering elastic energy for further formation of infinitesimal amount of one phase from the other in the ...two-phase coherent system are obtained. Zero driving force is shown to be a useful thermodynamic criterion for coherent equilibria, which not only has a clear physical meaning, but also is really convenient in coherent equilibria calculations. The coherent equilibrium equations are derived to directly demonstrate that the equilibrium compositions of phases in coherent equilibria depend on the overall alloy composition. In particular, the influence of the deviation of lattice parameter from Vegard’s law on the coherent spinodal, the field lines and the equilibrium compositions of coherent miscibility gap is examined in a regular binary solution. The calculated results show that even small deviation of lattice parameter from Vegard’s law can make the equilibrium compositions strongly dependent on the overall alloy composition. Therefore, the deviation of lattice parameter from Vegard’s law should be carefully considered in the calculation of coherent phase diagrams of the realistic systems.
► Zero driving force is shown to be a useful criterion for coherent equilibria. ► The expressions of driving force considering elastic energy are obtained. ► The coherent equilibrium equations are derived based on zero driving force criterion. ► The influence of the deviation from Vegard’s law on coherent equilibria is examined.
A complete thermodynamic description of the BiaMgaSn ternary system was obtained by means of the CALPHAD (CALculation of PHAse Diagram) technique. The solution phases, Rhomb, Bct_A5 and Hcp_A3, are ...modeled with RedlichaKister equation. The associate model has been used to describe the liquid phase with the constituents of the species Bi, Bi2Mg3, Mg, Mg2Sn and Sn. The non-stoichiometric compounds Mg2Sn and alpha -Bi2Mg3 as well as its high temperature variant beta -Bi2Mg3 were described by the sublattice models (Bi,Mg)2(Bi,Sn)1, (Bi,Sn,Va)2Mg3 and (Bi,Sn)1(Bi,Sn,Va)3Mg6, respectively. The BiaMgaSn ternary system has been modeled thermodynamically for the first time and the calculated phase equilibrium relations and thermochemical properties are consistent with the experimental results available in literatures.
The Ge-Nd has been critically assessed by means of the CALculation of PHAse Diagram (CALPHAD) technique. For the liquid phase, the associate model was used with the constituent species Ge, Nd, Ge3Nd5 ...and Ge1.6Nd in the Ge-Nd system. The terminal solid solution diamond-(Ge), dhcp-(Nd) and bcc_A2-(Nd) in the Ge-Nd system were described using the substitutional model, in which the excess Gibbs energy was formulated with the Redlich-Kister equation. The compounds with homogeneity ranges, α(Ge1.6Nd), β(Ge1.6Nd), (GeNd), (Ge4Nd5) and (Ge3Nd5) were modeled using two sublattices as α(Ge,Nd)1.6Nd, β(Ge,Nd)1.6Nd, (Ge,Nd)Nd, (Ge,Nd)4Nd5 and (Ge,Nd)3Nd5, respectively. A set of self-consistent thermodynamic parameters for each of the Ge-Nd binary systems was obtained. The calculation results agree well with the available experimental data from literatures.
With the large-scale construction and operation of the metro, the urban power grid has seen the intrusion of metro stray currents causing transformer DC paramagnetism, resulting in increased ...transformer vibration and noise, and increased probability of failure. This paper firstly introduces the propagation path of transformer vibration, theoretically analyses the vibration spectral characteristics of transformer DC bias operation, and then through the vibration measurement of a 500kV transformer, the measured data will be subjected to spectral analysis, time-domain analysis, as well as the analysis of acceleration in different positions and different axial directions of the transformer, and obtains the influence law of stray currents on the vibration of the transformer.
The main content of the intelligent test of relay protection is to carry out the automatic intelligent test of the relay protection device to ensure its reliable operation. This task puts forward new ...requirements for the current traditional convolutional neural network architecture. The goal of intelligent testing of power equipment relay protection is to change the relay protection equipment of input power into a new one through the test of relay protection equipment to be used for computer program entry or system monitoring. Based on the above background, this paper proposes an intelligent test model of power equipment relay protection based on a machine learning algorithm. It improves the test quality through the above processing method of relay protection equipment. The machine learning algorithm model mainly relies on adversarial network testing and autoencoder to realize. In this paper, the basic tasks of the relay protection intelligent test are different, and the relay protection intelligent test methods are respectively designed and optimized.
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