Papers by Keyword: Interfacial Energy

Abstract: Steel alloys with high Mn and low C, low Cr wt.%, were designed based on the composition system for traditional high toughness, creep resistance, and longevity for high-temperature applications. In terms of energy resource utilization during production and refining, CALPHAD strategical optimization is preferable for all steel alloys. Thermo-Calc software calculates the phase diagrams α-BCC (Ferrite), and M₂₃C₆ (carbide) phases. The vital temperatures which are highlighted in this work are Ac₃ (threshold temperature at which ferrite is fully transformed into austenite (α→γ)), and A₄ (the threshold temperature at which austenite is fully transformed into Delta ferrite (γ→δ)) are essential for phase transformations. JMatPro software is used to predict the mechanical properties of steel alloys. The interfacial energies with regards to alloying elements for M₂₃C₆ are calculated to be between ~0.272 J/m^-2 to ~0.328 J/m^-2 for α-BCC) matrix, while γ-FCC has interfacial energy ranges to be between ~0.132 J/m^-2 to ~0.168 J/m^-2. This paper focuses on investigating the effect of alloying elements on phase transformations, interfacial energy, coarsening rate of carbides, and many other mechanical properties such as toughness at high-temperature applications using CALPHAD strategies.

Abstract: Bulk, surface and interface thermodynamics of immiscible liquid alloys are considered within a unified theoretical framework. For bulk thermodynamic functions the exponential and the combined linear-exponential equations are discussed, obeying the 4th law of thermodynamics. Surface phase transition is discussed in details. For surface and interface thermodynamics the monolayer Butler equation is compared to the multilayer model. During further assessment of bulk thermodynamic data of immiscible liquid alloys their experimentally measured surface tension and interfacial energy should be also taken into account, coupled with the models presented here.

Abstract: Phase field models are widely used for the study of microstructures and their evolution. They can also be used as computer experiments. As computer experiments, they serve two important roles: (a) theoretical results which are hard to verify/validate experimentally can be verified/validated on the computer using phase field models; and, (b) when severe assumptions are made in a theory, they can be relaxed in the phase field model, and hence, results with wider reach can be obtained. In this paper, we discuss some such computer experiments in general, and the growth kinetics of precipitates in systems with tetragonal and cubic interfacial anisotropies in particular.

Abstract: A Monte Carlo model is presented, in which the interface anisotropy is primarily inclination dependent. A dual grid method is used to determine boundary inclination in discretized digital microstructures. Evolution of the grain boundary character distribution (GBCD) in polycrystalline systems, from an initially random distribution, is inversely correlated with the anisotropy in interfacial energy, as expected.

Abstract: Solubility, metastable zone width and induction period of (R)-3-(methylamino)-1-phenylpropanol hydrochloride (MPH) in ethanol were determined by synthetic method at atmospheric pressure. The measured induction period data are also used to estimate the interfacial tension values of the system. The determined interfacial tension values have been also used to evaluate the nucleation parameters, such as the radius of the critical nuclei, the free energy change per unit volume, the critical free energy barriers.

Abstract: The interfacial energy and diffusion phenomenon of the Al₂O₃(012)-SiC (011) interface model are studied based on molecular dynamics. The interfacial energy increases firstly until reaches its maximum 0.459J/m² at the temperature of 1500K and then decreases. The relationship of diffusion coefficients for each kind of atoms is C>Si>O>Al. Diffusion coefficients of atoms increase at first and then decrease as the temperature goes up. This indicates the diffusion mechanism has been changed during the temperature rising process.

Abstract: The preference of the habit planes (HPs) developed from precipitation in the fcc/bcc system has been investigated. The interfacial energy of different interface orientations has been examined with variation of the orientation relationships (OR) and lattice parameters by a classical molecular dynamics method. The results show that interface has the lowest interfacial energy when it contains parallel Burgers vectors and a set of dislocations. The local minimum of interfacial energy may not associated with a maximum of dislocation spacing. It is also found that the near Kurdjumov-Sachs OR is more preferable than the near Nishiyama-Wasserman OR. Contrary to the previous interfacial energy calculations, which usually limit to rational ORs, the present work allows ORs to be irrational, which agrees with the observations.

Abstract: Wettability of solid surfaces is one of very important properties, which is governed by both the interface energy and the microstructures. In the paper, four microstructure surfaces were designed such as square concave, column concave, square convex and column convex. The contact angle and wettability of solid surfaces with regular microstructures were discussed for five contact angle models such as Young, Wenzel, Cassie, Cassie-Baxter and Wenzel-Cassie models. Then, the impacts of interfacial energy and microstructures to wettability were analyzed. The study shows that the character of hydrophobic or hydrophilic is decided by the interfacial energy between solid and liquid, and the wettability can be changed by adjusting the parameters of microstructures, such as the ratio of transverse spacing and diameter α, the ratio of longitudinal spacing and diameter β, the ratio of the deep and diameter γ or the ratio of soaking deep and diameter λ. And, the convex microstructure is more propitious to hydrohobic surface than concave microstructure.

Abstract: Interfacial energies are essential in modelling nucleation, growth and coarsening processes in solid materials; especially nucleation rates respond very sensitively to small changes of this quantity. Thus, the prediction of interfacial energies has attracted the interest of many researchers since many years. In this work, a simple concept for the calculation of energies of coherent interfaces in multicomponent systems is presented. The model advances the classical nearest-neighbor-broken-bond concept for arbitrary interface orientations and interface curvature. The obtained result is simple enough to be expressed in a single, closed equation. Consequently, it can be easily implemented in the framework of classical nucleation theory, or in complex simulation tools for precipitate evolution based on Kampmann-Wagner type models. In this paper, the theoretical background of the model is discussed, and the results are compared to experimental data. Furthermore, a size correction function for small precipitates is presented and applied to the prediction of nucleation rates. Despite the simplicity of the model, the predictions of the model are found to be in satisfactory agreement with experimental evidence.