Ultralight Metallic Microlattices

This paper deals with the bonding properties of 3d-, 4d-, and 5d-transition-metal carbides and nitrides. We consider NaCl-structure compounds, MC and MN, as well as carbides and nitrides with more complex crystal structures. The enthalpies of formation at zero temperature ${\mathrm{\ensuremath{\Delta}}}^{0}$H(0) of the MC and MN compounds are taken from previous ab initio linear-muffin-tin-oribtals calculations. We describe the structure as formed by a metal fcc lattice in which nonmetal atoms have been inserted at interstitial positions. ${\mathrm{\ensuremath{\Delta}}}^{0}$H(0) is divided into contributions from (i) formation of metallic fcc lattice, (ii) expansion of this lattice to the lattice spacing of the compound, and (iii) insertion of nonmetal atoms into the metal lattice. ${\mathrm{\ensuremath{\Delta}}}^{0}$H(0), plotted versus the position of M in the d series, shows a pronounced maximum for the Ti, Zr, and Hf carbides. In agreement with other work, we interpret this as due to the filling of bonding p-d hybridized states. The maximum in ${\mathrm{\ensuremath{\Delta}}}^{0}$H(0) is followed first by a decrease and then by an almost constant value. We interpret this as an effect of a gradual population of antibonding and nonbonding electronic states. Size effects, i.e., contribution (ii), are small for the 4d- and 5d-series compounds. ${\mathrm{\ensuremath{\Delta}}}^{0}$H(0) of MN is similar to that of MC, but the largest values occur for M=Sc,Y,La since N has one more valence electron than C. Bonding in the complex carbides and nitrides is given an analogous interpretation.

Researchers seeking to enhance the properties of metals have long pursued incorporating carbon in the metallic host lattice in order to combine the strongly bonded electrons in the metal lattice that yield high ampacity and the free electrons available in carbon nanostructures that give rise to high conductivity. The incorporation of carbon nanostructures into the copper lattice has the potential to improve the current density of copper to meet the ever-increasing demands of nanoelectronic devices. We report on the structure and properties of carbon incorporated in concentrations up to 5 wt. % (∼22 at. %) into the crystal structure of copper. Carbon nanoparticles of 5 nm–200 nm in diameter in an interconnecting carbon matrix are formed within the bulk Cu samples. The carbon does not phase separate after subsequent melting and re-solidification despite the absence of a predicted solid solution at such concentrations in the C-Cu binary phase diagram. This material, so-called, Cu covetic, makes deposition of Cu films containing carbon with similar microstructure to the metal possible. Copper covetic films exhibit greater transparency, higher conductivity, and resistance to oxidation than pure copper films of the same thickness, making them a suitable choice for transparent conductors.

A floating magnet model [5, 6] originally devised for simulating effects in superconductors has been modified to simulate metal and alloy lattices. The model shows grain boundaries, edge dislocations and point defects in the metal lattice, demonstrating the pinning of dislocations by impurity atoms and the drift of impurities to grain boundaries. Although the alloy was disordered for most concentrations, a stable ordered square lattice was formed readily at equal proportions of the two atoms. Defects, particularly dislocations, were more complicated in the ordered alloy than in the simple metal.

We present a numerical study of the electromagnetic properties of the three-dimensional metallic wire lattices operating at microwave frequencies with applications to advanced accelerating structures and microwave sources. The metallic lattices can be considered as “artificial plasmas” because they demonstrate the properties of plasmas with a negative dielectric constant. Bulk modes in a diamond lattice of metal wires and surface modes on its interface are calculated. It is shown that the lattice can be modeled as an anisotropic medium with spatial dispersion. In contrast to a simple cubic lattice, the diamond lattice allows the existence of three different interfaces—one isotropic and two anisotropic. The surface modes supported by these interfaces are affected by spatial dispersion, in sharp contrast with the surface mode on an isotropic vacuum/plasma interface. For particle accelerator applications, we identify the electromagnetic mode confined by a plasmonic waveguide formed as a defect in a diamond lattice. All deleterious higher order modes excited as wakefields from the accelerating particle are found to be leaky. The diamond lattice is also useful as a research tool for studying particle radiation in media with spatial dispersion.

A new cutting tool filled with metallic lattice and design method for vibration suppression in milling

The paper is focused on numerical studies of electromagnetic properties of composite materials used for the construction of small airplanes. Discussions concentrate on the homogenization of composite layers with metal lattice and composite layers with metal lattice with a slot. The homogenization is aimed to reduce CPU-time demands of EMC computational models of electrically large airplanes. First, a methodology of creating a 3-dimensional numerical model of a composite material with metal lattice in CST Microwave Studio is proposed focusing on a sufficient accuracy of the model. Second, two different approaches to homogenizing the composite with metal lattice are discussed. The proposed approaches are evaluated and compared from the viewpoint of the efficiency, the accuracy, the convergence, and hardware requirements. The obtained field distribution is compared with the distribution computed for the original composite walls.

It was confirmed that nanometer-sized metal powder (atom clusters or simply clusters) can absorb an extremely large amount of deuterium/hydrogen atoms more than 300% against the number density of host metal. Within such clusters, the bonding potential widely changes from the center region to peripheral ones, so that the zig•zag atom-chains are always formed dynamically around the average position of atoms and the degree of filling up of the constituent atoms for the fcc type metal reduces to about 0.64 from 0.74 in bulk metal, i.e., vacant space increases to 0.36 from 0.26. As a result, a large amount of deuterium /hydrogen atoms are instantly dissolved into such host-clusters at room temperature. Furthermore, “metallic deuterium lattice”(or hydrogen one) including locally the“deuterium-lump”with the ultrahigh density is formed with body centered cuboctahedral structure which belongs to a unit cell of the host lattice, while such event cannot be realized at all within bulk metals. It seems that nuclear fusion in solid (“solid fusion”) takes place in the highly condensed“deuterium-lump”inside each unit cell of the“metallic deuterium lattice”(or mixed hydrogen one) which is formed inside each cell of the host metal lattice. It is considered, therefore, that each unit cell of the host lattice corresponds to minimum units of“solid fusion reactor”. In order to achieve“solid fusion”, just the generation of the ultrahigh density“deuterium-lump”(simply“pycnodeuterium-lump”) coagulated locally inside unit cell of the host lattice and/or the highly condensed metallic deuterium lattice should be an indispensable condition.

The inherent damping deficiency in metal lattice structures leads to inadequate attenuation of both resonant peaks and shock-induced vibrations, significantly limiting their effectiveness in vibration isolation and shock resistance applications. To address this limitation, we developed a novel parallel polyurea method that utilizes the viscoelastic energy dissipation mechanism of polyurea to substantially improve structural damping performance. The metal lattice–polyurea parallel vibration isolation system was designed with its theoretical model established to characterize damping properties, vibration isolation, and shock-resistant performance. An experimental setup was developed to validate theoretical predictions through controlled semi-sinusoidal shock and swept-frequency tests. Experimental results demonstrate excellent agreement with theoretical predictions. The introduction of the polyurea damping structure significantly enhances the system’s damping performance. Compared to the conventional metal lattice isolator, the proposed metal lattice–polyurea parallel composite structure shows remarkable damping improvements: under shock excitation, it achieves substantial attenuation of peak response amplitude with accelerated decay rate, while under frequency-sweep excitation, it maintains the original resonance frequency but reduces the transmissibility peak significantly.

This work is aimed at the interactions between hydrogen atoms contained in high concentrations in metal lattices. Effects of metals on hydrogen interactions are surveyed by carrying out molecular dynamics (MD) simulations on hydrogen fluids containing palladium atoms, from a viewpoint in contrast to previous simulations on low concentrations of hydrogen in metal lattices. Some results of these simulations reveal the dissociation of H2 molecules to H atoms due to the presence of Pd atoms under densification, and therefore imply the change of attractive H-H interactions in H2 molecules to repulsive interactions of H atoms in Pd lattices. These repulsive interactions are consistent with an empirical “2-Å rule” of hydrogen atoms in metal lattices, and impose limits on hydrogen-storage capacities of metals.

The Gibson-Ashby model for additively manufactured metal lattice materials: Its theoretical basis, limitations and new insights from remedies

Performance of chocolate bar-shaped modular thermal management system combined metal lattice liquid-cooling plate with paraffin in high-rate discharge

A review on metallic micro lattice

The utilization of the triply periodic minimal surface (TPMS) has emerged as a highly effective approach for designing lattice structures due to its smooth surfaces, intricately connected lattice structures, and precisely controlled geometric properties. However, the full potential of metallic TPMS lattice structures remains underexplored due to three primary challenges: (i) the computational complexity involved in multi-scale design optimization, (ii) manufacturing limitations in achieving defect-free lattice architectures, and (iii) an incomplete understanding of the process-structure-property relationships necessary for multifunctional applications. To address this gap, a comprehensive analysis encompassing design, manufacturing, properties, and applications is essential. This paper presents such a study of metallic TPMS lattice structures. First, we introduce geometric design methods for generating digital TPMS models tailored to specific requirements. Building on this, we summarize additive manufacturing techniques employed in fabricating these structures, highlighting how additive manufacturing mitigates structural design constraints and enables high-quality, accurate fabrication. Subsequently, we elaborate on the diverse properties and multidisciplinary applications of additively manufactured metallic TPMS lattice structures. Finally, by synthesizing recent advancements in this field, we discuss existing limitations and offer perspectives on future research directions.

Ballistic resistance of hybrid-cored sandwich plates: Numerical and experimental assessment

The impact responses and ballistic resistance of the metal encapsulating ceramic composite armors with same area density and two hybrid cores are investigated. The hybrid cores include square metallic lattice with ceramic block insertions, and square metallic lattice with ceramic ball insertions and void-filling epoxy resin. Three-dimensional (3D) finite element (FE) simulations are carried out for each composite armors impacted by bullet with 12.7mm diameter. The focus is placed on the energy absorption capabilities and ballistic limit velocity of different composite armors. Results indicate that two kind of armors can improve the ballistic resistance properties and save mass of 22% and 25% compared to the homogeneous 4340 steel, respectively.