Phase-field crystal simulation of evolution of liquid pools in grain boundary pre-melting regions

Tian, Xiaolin; Zhao, Yuhong; Peng, Dunwei; Guo, Qianqian; Guo, Zhen; Hou, Hua

doi:10.1016/s1003-6326(21)65570-x

Cited by 35 publications

(8 citation statements)

References 48 publications

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“…Nevertheless, there is evidence of a weak and range-limited pre-melting effect on heating from the solid phase. The basic model explanation suggests the fragmentation of the solid into crystalline grains covered by quasi-liquid nanolayers [ 46 , 59 , 60 , 61 , 62 , 63 ]. However, the volume associated with these nano-layers is (very) minimal compared to the volume occupied by solid, crystalline grains.…”

Section: Resultsmentioning

confidence: 99%

The Dominance of Pretransitional Effects in Liquid Crystal-Based Nanocolloids: Nematogenic 4-methoxybenzylidene-4′–butylaniline with Transverse Permanent Dipole Moment and BaTiO3 Nanoparticles

Drozd-Rzoska,

Łoś,

Rzoska

2024

Nanomaterials

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The report presents static, low-frequency, and dynamic dielectric properties in the isotropic liquid, nematic, and solid phases of MBBA and related nanocolloids with paraelectric BaTiO3 nanoparticles (spherical, d = 50 nm). MBBA (4-methoxybenzylidene-4′–butylaniline) is a liquid crystalline compound with a permanent dipole moment transverse to the long molecular axis. The distortions-sensitive analysis of the dielectric constant revealed its hidden pretransitional anomaly, strongly influenced by the addition of nanoparticles. The evolution of the dielectric constant in the nematic phase shows the split into two regions, with the crossover coinciding with the standard melting temperature. The ‘universal’ exponential-type behavior of the low-frequency contribution to the real part of the dielectric permittivity is found. The critical-like pretransitional behavior in the solid phase is also evidenced. This is explained by linking the Lipovsky model to the Mossotti catastrophe concept under quasi-negative pressure conditions. The explicit preference for the ‘critical-like’ evolution of the apparent activation enthalpy is worth stressing for dynamics. Finally, the long-range, ‘critical-like’ behavior of the dissipation factor (D = tgδ), covering the isotropic liquid and nematic phases, is shown.

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Section: Resultsmentioning

confidence: 99%

The Dominance of Pretransitional Effects in Liquid Crystal-Based Nanocolloids: Nematogenic 4-methoxybenzylidene-4′–butylaniline with Transverse Permanent Dipole Moment and BaTiO3 Nanoparticles

Drozd-Rzoska,

Łoś,

Rzoska

2024

Nanomaterials

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“…Equation (1) is numerically solved by the semi-implicit Fourier spectral method [ 16 ].

[ 17 ] is given by:

where

, and

are the local free energy densities of total, Landau, gradient, elastic, and electrostatic energies, respectively, and

is the volume of the KNN thin film.…”

Section: Methodsmentioning

confidence: 99%

Alternating Current Field Effects in Atomically Ferroelectric Ultrathin Films

Cao

Liu

et al. 2022

Materials

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In this work, atomically K1−xNaxNbO3 thin films are taken as examples to investigate the reversible and irreversible effects in a horizon plane, i.e., the changes of domain structures, phase states, free energies, etc., under a z-axis alternating current field via a phase-field method. The simulation results show the driving forces during the charging and discharging process, where there is a variation for the angles of the domain walls from 180° to 90° (and then an increase to 135°), which are the external electric field and domain wall evolution, respectively. As for the phase states, there is a transformation between the orthorhombic and rhombohedral phases which can’t be explained by the traditional polarization switching theory. This work provides a reasonable understanding of the alternating current field effect, which is essential in information and energy storage.

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“…The phase-field-crystal (PFC) model reflecting the information on the diffusion time scale (10 −6 s), makes up for this shortcoming, which fully reveals the influence of atomic effect. The PFC model [16] developed in recent years is the microscopic form of Cahn-Hilliard and Allen-Cahn equations [17][18][19][20] at the atomic scale, which can reflect the periodicity of the crystal lattice. This method characterizes the evolution of microstructure by constructing free energy equation and explores the effects of different processing techniques (temperature, [21,22] orientation angle, [23][24][25] strain mode, strain size, etc.)…”

Section: Introductionmentioning

confidence: 99%

Phase-field-crystal simulation of nano-single crystal microcrack propagation under different orientation angles

et al. 2023

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The propagation mechanism of microcracks in nanocrystalline single crystal systems under uniaxial dynamic and static tension is investigated using the phase-field-crystal method. Both dynamic and static stretching results show that different orientation angles can induce the crack propagation mode, microscopic morphology, the free energy, and crack area change, causing fracture failure. Crack propagation mode depends on the dislocation activity near the crack tip. Brittle propagation of the crack occurs due to dislocation always at crack tip. Dislocation is emitted at the front end of the crack tip and plastic deformation occurs, which belongs to ductile propagation. The orientation angles of 9° and 14° are brittle-ductile mixed propagation,<br/> while the orientation angles of 19° and 30° are brittle propagation and no dislocation is formed under dynamic tension. The vacancy and vacancy connectivity phenomenon would appear when the orientation angle is 14° under static tension, and the crack would be ductile propagation. While the orientation angle is 19° and 30°, The crack propagates in a certain direction, which is a kind of brittle propagation. This work has some practical significance in preventing material fracture failure and improving material performance.

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Phase-field crystal simulation of evolution of liquid pools in grain boundary pre-melting regions

Cited by 35 publications

References 48 publications

The Dominance of Pretransitional Effects in Liquid Crystal-Based Nanocolloids: Nematogenic 4-methoxybenzylidene-4′–butylaniline with Transverse Permanent Dipole Moment and BaTiO3 Nanoparticles

The Dominance of Pretransitional Effects in Liquid Crystal-Based Nanocolloids: Nematogenic 4-methoxybenzylidene-4′–butylaniline with Transverse Permanent Dipole Moment and BaTiO3 Nanoparticles

Alternating Current Field Effects in Atomically Ferroelectric Ultrathin Films

Phase-field-crystal simulation of nano-single crystal microcrack propagation under different orientation angles

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