Metal Boundary Research Articles

Research of the microstructure glass–metal boundary obtained under influence by ultrashort pulse lasers

The article research the microstructure of the welded layer obtained by exposure to an ultrashort laser pulse on a glass-metal joint. The study of the weld made it possible to identify the effect of thermal diffusion of the chemical elements of glass and metal into the joint zone in a ratio of 50 : 50% of each material. The size of the transition layer of the welded joint between glass and metal was 2–3 microns. The results of the work also show that when combining chromium-nickel stainless steel with borosilicate glass, bonds of the Fe–O–Si type are formed, and the connection of a 6000 series aluminum alloy with borosilicate glass leads to the formation of aluminum oxides Al2O3.

Model-based dimensional NDE from few X-ray radiographs: Application to the evaluation of wall thickness in metallic turbine blades

The extraction of 3D dimensional measurements based on a limited number of 2D X-ray radiographs of a part would offer a significant speed-up of quality control procedures in industry. However, there are challenges with respect to both measurements and uncertainties. This work addresses these challenges by creating an estimated numerical model of the imaged part on which dimensional measurements can be made. The numerical model is chosen as a parametric deformable model that encodes the expected shape variability of the parts resulting from the manufacturing process. The parameters and uncertainties of the numerical model of the imaged part are estimated by the registration of the computed projections of the model and the observed radiographs without the need of any segmentation. The registration requires the model, the initial parameters, and the observed radiographs. The proposed approach is applied to the inspection of turbine blades manufactured by investment casting, and in particular to the measurement of their wall thickness, which is a critical control. The deformable model consists in partitioning the inner ceramic core into multiple subparts, which may undergo a rigid body motion with respect to the master die. Wall thickness measurements are determined from the estimation of these rigid body motions. To assess the reliability of the proposed procedure, a repeatability study is performed. In addition, wall thickness measurements were compared to corresponding measurements from the surface of the metal boundary obtained by X-ray computed tomography. This surface was determined from a reconstructed tomogram using commercial software. Both analyses show that such measurements are reliable and efficient. Furthermore, residual differences between captured and computed projections reveal localized shape deviations from the CAD model, meaning that despite localized model errors, the approach is operable.

Image charge effects under metal and dielectric boundary conditions.

Theimage charge(IC)effect is a fundamental problem in electrostatics. However, proper treatment at the continuum level for many-ion systems, such as electrolyte solutions or ionic liquids, remains an open theoretical question. Here, we demonstrate and systematically compare the IC effects under metal and dielectric boundary conditions (BCs), based on a renormalized Gaussian-fluctuation theory. Our calculations for a simple 1:1 symmetric electrolyte in the point-charge approximation show that the double-layer structure, capacitance, and interaction forces between like-charged plates depend strongly on the types of boundaries, even in the weak-coupling regime. Like-charge attraction is predicted for both metal and dielectric BCs. Finally, we comment on the effects of a dielectricallysaturated solvent layer on the metal surface. We provide these results to serve as a baseline for comparison with more realistic molecular dynamics simulations and experiments.

Thermal Annealing Effect on Elastoplastic Behaviour of Al/Cu Bimetal during Three-Point Bending.

This paper presents the results of experimental studies on the effects of temperature and time of annealing on the elastoplastic properties of bimetallic aluminium-copper sheets. Mechanical tests were carried out on flat samples previously heated to temperatures of 250, 350, 450, and 500 °C for 40, 90, and 150 min. At the beginning of the tests, the elastic constants and internal friction energy were determined after thermal exposure using the impulse vibration exposure method. Further tests were carried out on the same samples using the three-point bending test. Based on the tests, the following quantities were determined and analysed: elasticity angles, translocations of the neutral axes of the cross-sections of samples, and changes in the values of bending moments plasticizing the extreme layers of bimetallic Al/Cu samples resulting from thermal interactions. The final part of this paper presents the results of measurements of the thickness of diffusion zones at the interface and their effect on the stability of the joint after annealing. The studies that were conducted indicate the dominant influence of the thermal factor on the properties of the Al/Cu bimetal above the temperature of 350 °C, which leads to the weakening of its strength and the degradation of the structure at the metallic phase boundary.

Coupled model for liquid lithium plasma facing components

Numerical analysis provides the design choice and operating window of liquid metal Plasma Facing Components (PFC) concepts. Coupled analysis of boundary plasma together with the surrounding boundary structures is required. To achieve this goal, PPPL is developing a comprehensive multi-physics model for modeling of PFCs in fusion devices. The model includes the fluid-kinetic code SOLPS-ITER and the flow and heat transfer code CFX from ANSYS. SOLPS-ITER was augmented with a liquid metal boundary condition algorithm, allowing direct two-way coupling of the plasma analysis with the two-dimensional analytical slab flow model which includes heat convection in the liquid metal PFC. The target heat flux resulting from this coupled analysis is used as a boundary condition for detailed 3D Computational Fluid Dynamics (CFD) Magneto Hydro Dynamics (MHD) and heat transfer analysis. A new formulation of MHD equations is introduced in the numerical procedure ensuring current conservation of the discretized equations. Results of the 3D analysis are used for final validation of the coupled model. A PFC design where a porous wall is used to stabilize the liquid metal surface, while MHD drive is used to push the liquid metal flow inside the PFC, will be investigated in the regimes where vapor shielding is created for enhanced volumetric plasma heat dissipation.

Анализ течений при лазерно-акустической обработке нержавеющей стали AISI 316L

The influence of ultrasonic vibrations on the flow of molten metal during laser processing is investigated. This problem is of interest within the context of modernization of existing technological processes, such as laser welding and cladding, for the production of structures with improved physical and mechanical properties. The introduction of additional ultrasonic energy into the liquid metal bath intensifies the metal flow via forced stirring, which provides its homogenization and leads to an increase in the mechanical properties of the processed material due to the growth of the number of crystallization centers during its solidification. In order to get a better understanding of this combined process and to control it, a method for synthesizing hydrodynamic and strength solvers used in the ANSYS software package is proposed. Setting up the coupling between two corresponding ANSYS Transient Structural and ANSYS CFX modules is executed through the additional ANSYS System Coupling module. Under this numerical implementation of the problem, it is possible to calculate the displacements at the solid metal boundary and their transfer to the liquid metal boundary and vice versa at each moment of time. The impact of laser radiation on the liquid metal is considered taking into account Marangoni convection, and convection and radiation heat transfer. The results of numerical experiments make it possible to conduct a qualitative and quantitative comparison between the liquid AISI 316L stainless steel flows formed without and with ultrasonic vibration. It is shown that the intensification and deceleration of the flows is observed at the average values of the ultrasonic amplitude. This fact correlates with the moments of time at which the deformed surface of the metal in the bath moves down and up. A comparative analysis of the maximum axial velocities inside the liquid metal bath was conducted. The absence of ultrasonic action on the liquid metal motion was observed at the maximum values of the vibration amplitude, which correspond to the maximum displacement and deformation of the surface at the interface between liquid and solid.

Erratum for the Research Article: "Complex dislocation loop networks as natural extensions of the sink efficiency of saturated grain boundaries in irradiated metals," by He et al.

Erratum for the Research Article: "Complex dislocation loop networks as natural extensions of the sink efficiency of saturated grain boundaries in irradiated metals," by He et al.

Ultra‐High Proportion of Grain Boundaries in Zinc Metal Anode Spontaneously Inhibiting Dendrites Growth

AbstractAqueous Zn‐ion batteries are an attractive electrochemical energy storage solution for their budget and safe properties. However, dendrites and uncontrolled side reactions in anodes detract the cycle life and energy density of the batteries. Grain boundaries in metals are generally considered as the source of the above problems but we present a diverse result. This study introduces an ultra‐high proportion of grain boundaries on zinc electrodes through femtosecond laser bombardment to enhance stability of zinc metal/electrolyte interface. The ultra‐high proportion of grain boundaries promotes the homogenization of zinc growth potential, to achieve uniform nucleation and growth, thereby suppressing dendrite formation. Additionally, the abundant active sites mitigate the side reactions during the electrochemical process. Consequently, the 15 μm Fs−Zn||MnO2 pouch cell achieves an energy density of 249.4 Wh kg−1 and operates for over 60 cycles at a depth‐of‐discharge of 23 %. The recognition of the favorable influence exerted by UP‐GBs paves a new way for other metal batteries.

Ultra-High Proportion of Grain Boundaries in Zinc Metal Anode Spontaneously Inhibiting Dendrites Growth.

Aqueous Zn-ion batteries are an attractive electrochemical energy storage solution for their budget and safe properties. However, dendrites and uncontrolled side reactions in anodes detract the cycle life and energy density of the batteries. Grain boundaries in metals are generally considered as the source of the above problems but we present a diverse result. This study introduces an ultra-high proportion of grain boundaries on zinc electrodes through femtosecond laser bombardment to enhance stability of zinc metal/electrolyte interface. The ultra-high proportion of grain boundaries promotes the homogenization of zinc growth potential, to achieve uniform nucleation and growth, thereby suppressing dendrite formation. Additionally, the abundant active sites mitigate the side reactions during the electrochemical process. Consequently, the 15 μm Fs-Zn||MnO2 pouch cell achieves an energy density of 249.4 Wh kg-1 and operates for over 60 cycles at a depth-of-discharge of 23 %. The recognition of the favorable influence exerted by UP-GBs paves a new way for other metal batteries.

Large-Gap and Topological Crystalline Insulating Phase in RbZnBi and CsZnBi.

Topological insulators (TIs) are a new class of materials with gapless boundary states inside the bulk insulating gap. This metallic boundary state hosts intriguing phenomena such as helical spin textures and Dirac crossing points. Here, we theoretically propose RbZnBi and CsZnBi as a new family of TIs exhibiting large bulk band gaps and unique gapless surface states. Our first-principles density functional calculations show that two materials can be stabilized in two different structures depending on the stacking order of hexagonal ZnBi layers. While both materials in the AA-stacked structure become TI, the AB-stacked RbZnBi and CsZnBi are topological crystalline insulators with hourglass-shaped Fermion surface states protected by nonsymmorphic glide symmetry. The calculated bulk gap is about 1.5-1.8 times larger than that of Bi2Se3, which makes RbZnBi and CsZnBi promising candidates for future applications.

Effect of the atomic structure of complexions on the active disconnection mode during shear-coupled grain boundary motion

The migration of grain boundaries leads to grain growth in polycrystals and is one mechanism of grain-boundary-mediated plasticity, especially in nanocrystalline metals. This migration is due to the movement of dislocationlike defects, called disconnections, which couple to externally applied shear stresses. While this has been studied in detail in recent years, the active disconnection mode was typically associated with specific macroscopic grain boundary parameters. We know, however, that varying microscopic degrees of freedom can lead to different atomic structures without changing the macroscopic parameters. These structures can transition into each other and are called complexions. Here, we investigate [111¯] symmetric tilt boundaries in fcc metals, where two complexions—dubbed domino and pearl—were observed before. We compare these two complexions for two different misorientations: In Σ19b[111¯](178) boundaries, both complexions exhibit the same disconnection mode. The critical stress for nucleation and propagation of disconnections is nevertheless different for domino and pearl. At low temperatures, the Peierls-like barrier for disconnection propagation dominates, while at higher temperatures the nucleation is the limiting factor. For Σ7[111¯](145) boundaries, we observed a larger difference. The domino and pearl complexions migrate in different directions under the same boundary conditions. While both migration directions are possible crystallographically, an analysis of the complexions' structural motifs and the disconnection core structures reveals that the choice of disconnection mode and therefore migration direction is directly due to the atomic structure of the grain boundary. Published by the American Physical Society 2024

Complex dislocation loop networks as natural extensions of the sink efficiency of saturated grain boundaries in irradiated metals.

The development of radiation-tolerant structural materials is an essential element for the success of advanced nuclear energy concepts. A proven strategy to increase radiation resistance is to create microstructures with a high density of internal defect sinks, such as grain boundaries (GBs). However, as GBs absorb defects, they undergo internal transformations that limit their ability to capture defects indefinitely. Here, we show that, as the sink efficiency of GBs becomes exhausted with increasing irradiation dose, networks of irradiation loops form in the vicinity of saturated or near-saturated GB, maintaining and even increasing their capacity to continue absorbing defects. The formation of these networks fundamentally changes the driving force for defect absorption at GB, from "chemical" to "elastic." Using thermally-activated dislocation dynamics simulations, we show that these networks are consistent with experimental measurements of defect densities near GB. Our results point to these networks as a natural continuation of the GB once they exhaust their internal defect absorption capacity.

Synergistic shielding of copper from nitric acid corrosion: Unveiling the mechanisms through electrochemical, characterization, and computational insights with 2-Hydroxybenzaldehyde oxime

Schiff-base metallic complexes have garnered considerable attention due to their unique attributes and broad applications across various sectors. Among these, organic Schiff-type bases have emerged as effective agents for mitigating corrosion in challenging environments. This study employs a comprehensive approach to assess the efficiency of 2-Hydroxybenzaldehyde oxime (HOBAO) in preventing copper corrosion. Synthesis and characterization of the HOBAO compound were conducted using FTIR and NMR (1H and 13C) analyses, confirming successful production. The inhibition performance on copper was investigated in a 1 M HNO3 medium utilizing gravimetric, electrochemical impedance spectroscopy, and potentiodynamic polarization techniques. Our findings reveal that HOBAO, at a concentration of 300 ppm, significantly inhibits corrosion, achieving rates of 82.00 %, 93.30 %, and 91.80 % for weight loss, polarization, and EIS analyses, respectively. SEM, EDS, and UV investigations provide evidence of the inhibitor's adsorption onto the copper surface, resulting in a smoother and more uniform appearance with minimal damage. Theoretical and practical results were meticulously compared, demonstrating that HOBAO acts as a mixed-type inhibitor with heightened effectiveness at higher concentrations of 300 ppm. SEM observations offer compelling evidence of inhibitor molecules exhibiting robust resistance against HNO3 attacks at the metal boundaries. Molecular modeling, including DFT and MD simulation studies, further support these findings, suggesting that the oxygen heteroatoms of HOBAO serve as favorable sites for molecular adsorption onto the copper surface. In conclusion, our comprehensive findings highlight HOBAO's potential as a promising copper corrosion inhibitor, particularly in environments containing nitric acid.

Quantum-informed plasmonics for strong coupling: the role of electron spill-out

The effect of nonlocality on the optical response of metals lies at the forefront of research in nanoscale physics and, in particular, quantum plasmonics. In alkali metals, nonlocality manifests predominantly as electron density spill-out at the metal boundary, and as surface-enabled Landau damping. For an accurate description of plasmonic modes, these effects need be taken into account in the theoretical modeling of the material. The resulting modal frequency shifts and broadening become particularly relevant when dealing with the strong interaction between plasmons and excitons, where hybrid modes emerge and the way they are affected can reflect modifications of the coupling strength. Both nonlocal phenomena can be incorporated in the classical local theory by applying a surface-response formalism embodied by the Feibelman parameters. Here, we implement local surface-response corrections in Mie theory to study the optical response of spherical plasmonic–excitonic composites in core–shell configurations. We investigate sodium, a jellium metal dominated by spill-out, for which it has been anticipated that nonlocal corrections should lead to an observable change in the coupling strength, appearing as a modification of the width of the mode splitting. We show that, contrary to expectations, the influence of nonlocality on the anticrossing is minimal, thus validating the accuracy of the local response approximation in strong-coupling photonics.

Metal Boundary Effect Mitigation by HKMG Thermal Process Optimization in FinFET Integration Technology

Metal Boundary Effect Mitigation by HKMG Thermal Process Optimization in FinFET Integration Technology

Atomic-level mechanisms of short-circuit diffusion in materials

Abstract This paper reviews the recent progress in understanding the atomic mechanisms of short-circuit diffusion along materials interfaces, such as grain and interphase boundaries, as well as lattice and interfacial dislocations/disconnections. Recent atomistic computer simulations have shown that short-circuit diffusion is dominated by collective atomic rearrangements in the form of strings and rings of mobile atoms. The process is dynamically heterogeneous in space and time and has many features in common with atomic dynamics in supercooled glass-forming liquids. We discuss examples of grain boundary, interphase boundary, and dislocation diffusion in metals and alloys, including the solute effect on the diffusion rates and mechanisms. Interphase boundaries are exemplified by Al–Si interfaces with diverse orientation relationships and atomic structures. The hierarchy of short-circuit diffusion paths in materials is reviewed by comparing the rates of grain boundary, interphase boundary, and dislocation diffusion. Future directions in the field of short-circuit diffusion in defect core regions are discussed.

Grain boundary and interface interaction of metal (copper/indium) oxides to boost efficient electrocatalytic carbon dioxide reduction into syngas

Electrochemical conversion of carbon dioxide (CO2) into syngas is considered a promising approach to mitigate global warming and achieve the recycling of carbon resources. In this work, a series of core–shell metal (copper/indium) oxides with abundant grain boundaries (GBs) between the amorphous In2O3 and cubic Cu2O have been prepared by template-assisted co-precipitation method and tested for the synthesis of syngas by electrochemical CO2 reduction reaction (CO2RR). The phases of Cu2O and In2O3 are independent in bimetallic oxides and do not form any alloy oxidation phase, thus Cu2O and In2O3 can maintain their crystal structure and chemical properties in bimetallic oxides. The Cu2O and In2O3 would been completely reduced to metallic Cu and In during CO2RR. The derived copper/indium possesses the maximum FE of CO (80 %) at −0.77 V vs. reversible hydrogen electrode (RHE) and a good stability of 10 h in an H-type cell. Further applied the copper/indium oxide in the MEA reactor, the FE of CO is more than 80 % at 2.6 V and the total FE of syngas is near 100 % at all applied potentials. More importantly, the H2/CO ratios can be tuned from 1/1 to 1/4 by changing the applied voltages in MEA. Therefore, this study provides a promising strategy to promote the electrocatalytic CO2RR conversion by creating abundant grain boundaries in bimetallic oxides to regulate the ratio of H2/CO.

3D characterization of abnormal grain growth in nanocrystalline nickel

AbstractAbnormal grain growth, a pervasive phenomenon witnessed during the annealing of nanocrystalline metals, precipitates a swift diminution of the distinctive properties inherent to such materials. Historically, conventional transmission electron microscopy has struggled to efficiently procure comprehensive five‐parameter crystallographic information from a substantial number of grain boundaries in nanocrystalline metals, thus inhibiting a deeper understanding of abnormal grain growth behavior within nanocrystalline materials. In this study, we utilize a high‐throughput characterization method—three‐dimensional orientation mapping in the TEM (3D‐OMiTEM) to characterize the crystallographic five‐parameter character of grain boundaries with an area of over 3.4 × 106 nm2 in an abnormally grown nanocrystalline nickel sample. When coupled with existing theoretical simulation results, it is discerned that the grain boundary population shows a relatively large scatter when it is correlated to the calculated grain boundary energy; the grain boundaries of abnormally grown grains exhibit lower grain boundary energy compared to those that have not undergone abnormal growth. Merging high‐throughput grain boundary information obtained from three‐dimensional orientation mapping data with grain boundary properties derived from high‐throughput theoretical calculations following the concept of materials genome engineering will undoubtedly facilitate further advancements in comprehending and discerning the interfacial behaviors of crystalline materials.

Disordering complexion transition of grain boundaries in bcc metals: Insights from atomistic simulations

Complexion transitions (CTs) of grain boundaries (GBs) have been a subject of extensive discussions in the last years, but many aspects of this phenomenon are still unclear. Here we studied temperature-induced disordering transitions of GBs in several body-centered cubic metals by means of classical atomistic simulations. Our study shows that gradual heating from room temperature to the melting temperature (Tm) leads to continuous disordering of the GB structure due to spontaneous formation of point defects in all studied metals. This disordering is accompanied by two CTs and exhibits analogies to transitions described by the Berezinskii–Kosterlitz–Thouless–Halperin–Nelson–Young theory. The first CT occurs at temperatures of about 0.7Tm and is characterized by significant changes of mechanical and kinetic properties. The second CT at about 0.9Tm is a premelting transition when the GB order parameter becomes zero.

Gold nanoparticles decorated MoS[formula omitted] nanosheets for sensing and degradation of carbamazepine in environmental wastewater

Trace pharmaceuticals and personal care products (PPCPs) have led to environmental contaminant and health risk. In this work, by in-situ reduction method, gold nanoparticles are loaded on the surface of the ultrathin MoS2 nanosheets to prepare AuNPs/MoS2 nanocomposites. AuNPs/MoS2 nanocomposites generate the superior localized surface plasmon resonance field due to the presence of nanogap between neighboring AuNPs and electron transfer within boundary of metal and semiconductor, which contributing great surface enhanced Raman scattering (SERS) effect. AuNPs/MoS2 nanocomposites-based SERS protocol is developed and successfully utilized to detect carbamazepine (CBZ) in wastewater. It presented a linear concentration ranging from 10−3 to 10−9 mol/L (R2=0.985) and a limit of detection about 1.36 × 10−10 mol/L, which foreboded the possibility for trace analysis. In addition, AuNPs/MoS2 nanocomposites with topological effect providing Mo4+ active sites and many defects present peroxidase-like activity to catalyze H2O2, forming radical oxide species (ROS) including ⋅OH, O2⋅− and 1O2. Herein, AuNPs/MoS2 nanocomposites as nanozyme with durability in environment are firstly used to catalytically degrade CBZ in wastewater by H2O2, showing high efficiency. Application of AuNPs/MoS2 nanocomposites as nanozyme to deal with pollution problems paves a promising paradigm for promoting the environmental and health safeties.