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Antiplane shear cracks in a harmonic square lattice have been studied in a molecular dynamics simulation. They can reach velocities larger than the shear wave velocity. 相似文献
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A. İyigör 《Philosophical Magazine Letters》2013,93(11):708-715
The structural, elastic and phonon properties of the quaternary CoFeCrZ (Z = Al, Si, Ga and Ge) Heusler alloys have been investigated using the generalized gradient approximation method within density functional theory. The ground-state properties, including, lattice constant and bulk modulus are in good agreement with the available theoretical and experimental data. The elastic constants Cij are computed using the stress–strain technique. The calculated results indicate that CoFeCrZ (Z = Al, Si, Ga and Ge) alloys are ductile materials. Debye temperatures are predicted from calculated elastic constants. The phonon dispersion relations of CoFeCrZ (Z = Al, Si, Ga and Ge) alloys are calculated for the first time using the density functional theory and the direct method with 2 × 2 × 2 supercell. 相似文献
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Nanoquasicrystalline Al-based alloys, containing icosahedral particles in an α-Al matrix, exhibit high strength at elevated temperature. The metastability of the quasicrystals can limit the use of these alloys. In the present work, the microstructural evolution of Al93(Fe3Cr2)7 and Al93Fe3Cr2Nb2 (at%) alloys was studied using heat treatments and structural characterization by XRD, TEM and STEM-EDX analysis. It was observed that the Nb is dissolved in the Al–Fe–Cr icosahedral phase. This provides higher thermal stability, retaining the fine nanoquasicrystalline microstructure for longer times at high temperature. 相似文献
4.
Weilong Hu 《Philosophical Magazine Letters》2013,93(1):7-14
A new physical concept, termed ‘equivalent strain-hardening work’, is proposed. The physical concept can be used to redefine the commonly used effective stress and effective strain theory as applied in constructing the constitutive relations of stress and strain, especially when related to an anisotropic strain-hardening material. The concept concerns that part of plastic work which emphasizes the action due to the strain-hardening behaviour of a material. Based on this concept, any one of the strain-hardening stress–strain curves obtained through common experiments on anisotropic materials can be selected as a nominally effective stress and an associated effective strain, and the rest of the strain-hardening relations can all be then transformed to be functions of variables of the nominally effective strain. Thus, any kind of loading path can be characterized by a single relation between effective stress and effective strain. When applied to the isotropic materials, the equivalent strain-hardening work concept is identical with the work-equivalent deformation concept but is more general. 相似文献
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The structural, elastic, electronic and phonon properties of HfX (X = Rh, Ru and Tc) in the caesium-chloride phase have been investigated using the density functional theory within the generalized gradient approximation. The optimized lattice constant (a0), bulk modulus (B) and the elastic constants (Cij) are evaluated. The results are in a good agreement with the available experimental and theoretical data in the literature. Electronic band structures and densities of states have been derived for these compounds. The present band structure calculations indicate that the phases of caesium-chloride HfX (X = Rh, Ru and Tc) compounds are metals. Phonon dispersion curves and their corresponding total and projected density of states have been obtained using the direct method. The phonon spectra suggest that these compounds are dynamically stable in the caesium-chloride phase. 相似文献
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本文介绍了一种将多维数据视觉化呈现的技术elastic模型.以及以该模型为理论基础开发的软件ViDaExpert。elastic模型与ViDaExpert使用便捷功能强大.可以帮助解决多维数据视觉呈现及数据分析问题。 相似文献
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M. Munawar Chaudhri 《Philosophical Magazine Letters》2017,97(9):343-349
A new schematic diagram is presented which shows the displacement paths of surface particles within the contact circle when a rigid cone is loaded normally on an elastic half-space. With the help of this diagram and the information available in the literature, it is argued here that a modification made to the Love equation in 1999 is unnecessary and incorrect. It is also shown that the modification results in an incorrect expression for the surface radial displacement outside the contact circle. Therefore, it is suggested that the modification be dropped forthwith. 相似文献
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On the determination of defect dipoles from atomistic simulations using periodic boundary conditions
Roberto C. Pasianot 《Philosophical Magazine Letters》2016,96(12):447-453
By solving the problem of a periodic distribution of point defects in general anisotropic media, we give an alternative, more direct proof, of the relatively recent procedure that extracts dipole tensors from the stress acting on the cell of atomistic simulations performed under periodic boundary conditions. Moreover, we show that naive superposition of individual defect fields is not a solution of the problem, though correction terms can be identified; as a byproduct, analysis of the latter allows us to reveal a spurious contribution to the elastic interaction energy as calculated in current literature procedures, that therefore must be subtracted in order to obtain correct results. 相似文献
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