Wei Xiao

• PhD
• GRIMAT Engineering Institute Co., Ltd.

Solid-state additive manufacturing (SSAM) is an emerging technology that offers a unique approach by avoiding the melting and solidification of metals during the fabricating process. As a result, it eliminates common solidification related defects like porosity and cracking. This method is characterized by low residual stress, low distortion, and t...

For graphene/copper (Gr/Cu) composites, achieving high-quality interfaces between Gr and Cu (strong interfacial bonding strength and excellent electron transport performance) is crucial for enabling their widespread applications in electronic devices. This study employs first-principles calculations and the nonequilibrium Green’s function method to...

In crossover Al-Mg-Zn alloys, the T-phase (Mg 32 (Al, Zn) 49 ) is crucial for reinforcement. The critical nucleation size of the precipitated T-phase is notably reduced by Cu addition, as well as the activation energy. There is a lack of theoretical research on the influence of Cu elements on the stability of T-phases and mechanical properties. In...

In 6000-series Al-Mg-Si alloys, Zn is commonly added to enhance the aging response for improved properties. However, the segregation of Zn to interfaces and its interaction mechanisms with strengthening phases remain unclear. Combining experiments and theoretical calculations, we systematically investigated Zn segregation behavior at the β″/Al inte...

This study investigated the microstructure and mechanical properties of AlNbTiVZr series high-entropy alloys (HEAs) through both experimental studies and density functional theory calculations. Significant improvements in the microstructures and mechanical properties were achieved for the AlNbTiVZr series HEAs by meticulously adjusting the alloy co...

Al–Li alloys, characterized by their lightweight and high strength, are essential structural materials in aerospace industry. Unraveling the atomic mechanisms that enhance the modulus of Al–Li alloys is key to developing the next-generation alloys. Utilizing first-principles methods, we systematically explored the influence of alloying elements on...

The inorganic solid‐state electrolytes play a crucial role in all‐solid‐state batteries. The entropy of solid‐state electrolytes has a significant impact on ion transport. It has been reported that ionic conductivity can be enhanced by increasing the entropy by adding multiple atoms to the materials. However, there is a lack of understanding regard...

Due to its exceptional oxygen storage/release capabilities, excellent catalytic activity, and selectivity, the single-atom Pt 1 /CeO 2 catalyst has demonstrated significant research prospects and development promise in fuel cell applications. Investigating how the Pt 1 /CeO 2 system behaves in oxygen-poor environments has become a focal point of cu...

In this work, the evolution of mechanical properties of binary Al–Li alloys with four approximately equal gradient Li contents (0.91–3.98 wt.%) under aging conditions is thoroughly investigated. The alloys undergo aging treatments at 175 °C for x hours (x = 0–120 h), and the peak-aged times of the four alloys are 6 h, 12 h, 48 h and 48 h, respectiv...

In the development process of crossover aluminum alloys, T-Mg32(Al, Zn)49 phases play a significant role in the precipitation strengthening effect. However, comprehensive understandings of the structural characteristics, interactions among alloying elements, mechanical property dependence on composition variation, effects of doping and defects etc....

Body-centered cubic refractory metallic materials exhibit excellent high-temperature strength, but often suffer from brittle intergranular fracture due to the recrystallization-induced enrichment of trace elements at grain boundaries (GBs). Here, we report a fully-recrystallized pure molybdenum (Mo) material with room temperature (RT) superplastici...

To investigate the comprehensive effects of the Al and Zr element contents on the microstructure evolution of the AlNbTiVZr series light-weight refractory high entropy alloys (HEAs), five samples were studied. Samples with different compositions were designated Al1.5NbTiVZr, Al1.5NbTiVZr0.5, AlNbTiVZr, AlNbTiVZr0.5, and Al0.5NbTiVZr0.5. The results...

As exciting candidates for next‐generation energy storage, all‐solid‐state lithium batteries (ASSLBs) are highly dependent on advanced solid‐state electrolytes (SSEs). Here, using cost‐effective LaCl3 and CeCl3 lattice (UCl3‐type structure) as the host and further combined with a multiple‐cation mixed strategy, we report a series of UCl3‐type SSEs...

As exciting candidates for next‐generation energy storage, all‐solid‐state lithium batteries (ASSLBs) are highly dependent on advanced solid‐state electrolytes (SSEs). Here, using cost‐effective LaCl3 and CeCl3 lattice (UCl3‐type structure) as the host and further combined with a multiple‐cation mixed strategy, we report a series of UCl3‐type SSEs...

Single-atom Pt1/CeO2 catalysts may cope with the high cost and durability issues of fuel cell electrocatalysts. In the present study, the stability and underlying interaction mechanisms of the Pt1/CeO2 system are systematically investigated using first-principles calculations. The Pt adsorption energy on CeO2 surfaces can be divided into chemical i...

The interface microzone characteristics determine the thermophysical properties of diamond/Cu composites, while the mechanisms of interface formation and heat transport still need to be revealed. Here, diamond/Cu-B composites with different boron content were prepared by vacuum pressure infiltration. Diamond/Cu-B composites up to 694 W/(mK) were ob...

The technical problem of copper additive manufacturing is expected to be solved through the size effect of nanomaterials. The molecular dynamics method was employed to understand the laser sintering process of single-crystal copper nanoparticles. Based on a theoretical characterization of the densification of nanocopper sintering developed at prese...

Graphene-based sensors typically fail in the selectivity of target gas detection when exposed to complex and multicompound atmospheres. We have thoroughly compared the adsorptions of various interfering gases (CO, NH3, CH4, C2H2, C2H4, CH3OH, and CH3Cl) with target HCHO on AgG and AgOG by first-principles simulations. The results demonstrate that A...

The structural and electronic properties of interfaces play an important role in the stability and functionality of solar cell devices. Experiments indicate that the SnO2/perovskite interfaces always show superior electron transport efficiency and high structural stability even though there exists a larger lattice mismatch. Aiming at solving the pu...

Chemically modifying graphene (such as chemical doping) is a commonly used method to improve its formaldehyde sensing properties, but the microscopic mechanisms of heteroatoms in the adsorption and sensing process are still unclear. In this paper, the adsorption and sensing properties of formaldehyde on graphene surfaces modified by X doping (X = B...

The interface property of perovskite solar cells (PSCs) is very important, which can influence the electron transmission efficiency and stability of the cells. In this text, we have discussed the stability and bonding characteristics of PbI 2 /TiO 2 interfaces by using the first-principles method. The PbI 2 /TiO 2 interfaces have a high interfacial...

Inorganic organic perovskite solar cells (PSCs) are a kind of solar cells with rapid development in recent years, but their poor environmental stability, such as the water degradation behavior, hinders their commercialization. Here, we have thoroughly studied the adsorption postures of water on CH 3 NH 3 PbI 3 surfaces. It is found that the adsorpt...

Compounds of rare earth zirconates with pyrochlore structure are candidates for the application of thermal barrier coatings of next generation. In order to modify the mechanic properties and maintain the low thermal conductivity, other trivalent rare-earth element substitution is commonly used. Presently, investigation on the evaluation of the prop...

One of the most challenging issues for a gas sensor is to achieve high selectivity when detecting the presence of particular gases in media mixed with other gases. A straightforward solution is to develop the sensing materials that can discriminate among several analytes in a mixture. Here we perform first-principles calculations for the adsorption...

All-solid-state batteries (ASSBs) have gained substantial attention because of their intrinsic safety and potentially high energy density. To enable ASSBs, developing solid-state electrolytes (SSEs) with high electrochemical stability is of foremost significance. Here we report a multi-metal chloride SSEs with an excellent electrochemical stability...

The thermal instability of organic-inorganic halide perovskite solar cell (PSC) is one of the most important factors restraining its commercialization. It has recently been reported that modifications at the interface...

The ability to tune the adsorption strength of the targeted gas on sensing materials is crucial for sensing applications. By employing first-principles calculations the adsorption and sensing properties of HCHO on small Pd n (n = 1-6) cluster decorated graphene have been systematically investigated. The adsorption energy is found to depend on the s...

Ni‐rich layered oxides are significantly promising cathode materials for commercial high‐energy‐density lithium‐ion batteries. However, their major bottlenecks limiting their widespread applications are capacity fading and safety concerns caused by their inherently unstable crystal structure and highly reactive surface. Herein, surface structure an...

The formaldehyde gas sensing properties of transition metal-doped graphene have been systematically investigated by first-principles calculations. The optimized geometries of transition metal-doped graphene with and without HCHO adsorption, adsorption energies, charge transfers and magnetic moments are obtained for various doped graphene systems. T...

The poor interface bonding between graphene and aluminum is one of the main challenges which could impede wider application of graphene/Al composites. Coating metals on graphene layer could be an effective method to solve this problem. In this research, the pullout processes and uniaxial tensile tests were performed by using molecular dynamics (MD)...

Interfacial Bi segregation in Sn-based solders is a critical issue that affects the reliability of solder joints. Doping alloying elements into Sn-Bi solders is considered as a potential way to improve the Bi precipitation. We provided insights into the mechanism of Bi segregation at the atomic scale, by calculating the dissolution and diffusion en...

Zr-doped ceria has been extensively been used in three-way catalyst industry due to the excellent physical and chemical properties. Co-doping technology is always employed to improve the stability of the materials by hindering the phase segregation into CeO 2 and ZrO 2 individual phases. In this paper, we have intensively studied the stability of M...

Organic−inorganic metal halide ABX3 perovskite materials have stimulated great interest because of their superior photoelectronic properties and potential solar cell applications. However, the most widely used CH3NH3PbI3 suffers from its poor stability and inclusion of toxic lead. In order to screen potential ABX3 candidate materials for solar cell...

In this paper, the mechanical properties of multilayer graphene embedded in aluminum matrix ([email protected]) under uniaxial tension were investigated using molecular dynamics (MD) simulation method. The results clearly show that the graphene layer could provide effective barriers against the dislocation propagation across the interfaces resultin...

Ceria, one of the most important functional rare-earth oxides, is widely used in many technically important industry fields. However, pure ceria is known to have poor thermal stability. Zirconia doping is usually employed to improve its thermal stability and achieve high OSC (oxygen storage capacity) performances under severe conditions. We have pe...

Ceria is one of the most important functional rare-earth oxides with wide industrial applications. Its amazing oxygen storage/release capacity is attributed to cerium’s flexible valence conversion between 4+ and 3+. However, there still exists some debate on whether the valence conversion is due to the Ce-4f electron localization-delocalization tra...

The redox property of CeO2 can be greatly enhanced by incorporating zirconium ions into the lattice to form a solid solution. However, the solid solution tends to separate into CeO2 and ZrO2 individual phases. Adding a third metal (M) into the system is likely to retard this behavior if M and Zr attract each other and form atomic pairs to make the...

Methylammonium lead iodide perovskites, CH3NH3PbI3, possess excellent photoelectric conversion properties and can be potentially applied as the next-generation light-harvesting layer of solar cells. However, the stability problems have been hindering their practical applications. The density-functional theory calculations have been performed to inv...

In this paper, crystallization characteristics of amorphous Ge2Sb2Te5 (a-GST) films induced by a Gaussian picosecond laser with different laser fluence were carried out using transmission electron microscopy (TEM), Raman spectra and ab initio molecular dynamics (AIMD) simulations. TEM observations presented a solid-state phase transition with nanoc...

TiNi 合金 B2 奥氏体中 Ti 位 Ni 诱导的晶格失稳 牛建钢 1 肖 伟 2 1 河北大学机械系 保定 071002 2 北京科技大学材料科学与工程学院 北京 100083 摘 要 提出了点缺陷扰动策略， 并利用此策略证实 Ti 位 Ni 实际上引起了 B2 奥氏体局域晶格失稳。失稳终态 相的结构特征是从扰动位出发的一维方向上的<100>B2原子列收缩和<111>B2原子列膨胀。失稳终态相的能量 低于 B2 相， 最低能量比 B2 相低 20 meV/atom， 在 Ti 位 Ni 浓度达到 2%~4%时出现。与奥氏体情况相反， Ti 位 Ni 无法令 B19′马氏体失稳。Ti 位 Ni 显著降低 TiNi 合金相变温度的现象一定程度上来源于此。 关键词 TiNi 合金，晶格失稳，...

A high-throughput method was employed to effectively obtain the cross-scale relationship of elastic copper alloys. Firstly, a Cu–Ni–Ti–Cu25Al–Cu35Sn diffusion multiple was prepared and heat-treated under a specified condition to form a series of diffusion layers with the concentration gradient at the multielement metal interface. Then, the composit...

Cerium oxides, such as CeO2 and Ce2O3, are of great scientific and technological importance for many potential applications. In this work, based on density functional theory (DFT), we performed systematic first-principles calculations to evaluate the performance of different exchange-correlation functionals, including the standard DFT (PBE, PBEsol)...

As a plasma facing material, tungsten (W) is exposed to high-flux hydrogen isotope plasma, enduring unwanted surface blistering. Here, we performed first-principles calculations on the interaction between H and W surfaces, aiming to understand the surface bubble formation. We calculated the energetics of H at the top-surface and sub-surface regions...

Nanocopper has become one of the research hotspots of metal powder for 3D printing, due to its excellent properties. In this paper, technical methods, process flow and research progress were systematically introduced of nanocopper powder for 3D printing. Preparation of nano-copper powder for 3D printing are mainly physical and chemical methods. Phy...

Limited tumor targeting and poor penetration of nanoparticles are two major obstacles to improving the outcome of tumor therapy. Herein, coadministration of tumor-homing peptide iRGD and multistage-responsive penetrating nanoparticles for the treatment of breast cancer are reported. This multistage-responsive nanoparticle, IDDHN, was comprised of N...

Density-functional theory calculations have been performed to systematically investigate the behaviors of solute atoms in 7000 series Al-Zn-Mg based alloys. It is found that solute atoms Mg and Zn are likely to segregate to $\Sigma$5(210)[001] tilt Al GB. The bonding environment and interface cohesion will be affected in different degree. Also, for...

A series of red-emitting Ca3ZrSi2O9:Eu³⁺,xBi³⁺ phosphors was synthesized using a conventional high temperature solid-state reaction method, for the purpose of promoting the emission efficiency of Eu³⁺ in a Ca3ZrSi2O9 host. The site preference of Bi³⁺ and Eu³⁺ in the Ca3ZrSi2O9 host was evaluated by formation energy. The effects of Bi³⁺ on electroni...

The surface composition segregation can have important effects on the catalytic and electrochemical properties of an alloy catalyst. We have performed density-functional theory (DFT) calculations to investigate the effects of a third transition metal (M) addition into the Ni3Mo alloy on the surface segregation and the stability of bulk-terminated a...

Solute H in Ti alloys has an important effect on their deformation and ductility, therefore changing the mechanical properties and improving the mechanical processing. We have performed first-principles calculations to investigate the effects of H on the mechanical properties of the hexagonal close packed α-Ti and the body centered cubic β-Ti, and...

Experiments observed preferential He bubble formation in carbide precipitates M23C6 during low-temperature He irradiation in ferritic-martensitic steels. However, the process and mechanism of He trapping in M23C6 present a challenge to measure. Using density functional theory, we have systematically investigated He distribution, migration, and accu...

Lu³⁺, with the smallest ionic radii in lanthanide ions, is an important and beneficial cation for tuning spectrum shifting toward a longer wavelength by ion substitution in many phosphors for solid-state lighting. However, in the Lu³⁺-substituted garnet system, the phosphor always has smaller lattice parameters and exhibits a shorter emission wavel...

We performe first-principles density functional theory calculations to investigate the stability and mechanical properties of various HfHx (0 ≤ x ≤ 1) phases. For pure Hf phases, the calculated results show that the HCP and FCC phases are mechanically stable, while the BCC phase is unstable at 0 K. Also, as for various HfHx phases, we find that H l...

The parametric optimization of process parameter in cold chamber die casting for an industrial component (copper motor rotors) was analyzed. The filling process was successfully simulated based on software FLOW-3D. The distribution of gas entrapment, temperature field and surface defect during the mold filling process were discussed in details. The...

We have performed first-principles density functional theory calculations to investigate the retention and migration of hydrogen in Be22W, a stable low-W intermetallic compound. The solution energy of interstitial H in Be22W is found to be 0.49 eV lower, while the diffusion barrier, on the other hand, is higher by 0.13 eV compared to those in pure...

Segregation at metal alloy surfaces has an important impact on their catalytic and chemical properties. We have performed density-functional theory calculations to investigate the surface segregation behaviors of Ni3M (M = Mo, Co, Fe) alloys in the presence of chemisorbed atomic oxygen. The calculated results show that the segregation trend at a Ni...

Commercial grade rolled and electrodeposited copper foils from Japan and China were selected, and their mechanical properties and microstructure were investigated. It was observed that there are notable differences in fracture strength, elongation at break and hydrophilicity between rolled and electrodeposited copper foils. The rolled copper foils...

The surface composition of an alloying system has an important impact on its catalytic and chemical properties. The segregation behavior of 3d, 4d and 5d transition metals on an Ni(111) surface has been investigated by performing first-principles calculations in the framework of density-functional theory with the generalized gradient approximation...

The authors wish to make the following corrections to this manuscript [1].[...]

The quaternary compound semiconductor Cu2ZnSnS4 (CZTS) is a promising photovoltaic absorber material for thin-film solar cell applications. Density-functional theory calculations have been performed to investigate the structural and electronic properties of the CdS/CZTS heterointerfaces in CZTS-based cells. We find that CdS favors epitaxial growth...

Chemisorbed atomic oxygen inducing Co segregation in CoNi (111) alloy is studied using periodic self-consistent density functional theory (DFT) calculations. In particular, the coverage dependence and possible adsorption-induced segregation phenomena are addressed by investigating segregation energies (the difference in calculated total free energy...

Segregation at metal alloy surfaces is an important issue because many electrochemical and catalytic properties are directly correlated to the surface composition. We have performed density functional theory calculations for Mo segregation in MoNi(111) in the presence of chemisorbed atomic oxygen. In particular, the coverage dependence and possible...

The catalytic reactivity is controlled by the binding strength between the catalyst surface and reaction intermediates. So our capability to tune the binding strength to an ideal value, i.e. the value corresponding to the top of the volcano relation, is crucially important. We have performed systematic density-functional theory calculations to inve...

The quaternary Cu2ZnSnS4 (CZTS) is a promising material for the thin-film solar cell applications. However, because CZTS is only stabilized in a very small chemical-potential region and the defect formation is much more complicated compared to the ternary systems, it requires careful control of the thin-film solar cell preparation. We have performe...

The formation energies and transition energies of intrinsic donor-like defects and various extrinsic impurities have been studied by first-principles calculations based on hybrid density functional theory, with the aim of exploring the sources of n-type conductivity in GaInO3. Our calculated results show that oxygen vacancies are deep donors; while...

Rare earth doping is widely used to improve the desired properties of high-k dielectric oxides. However, whether rare earth doping can suppress the formation of oxygen vacancies is still debated. By using the first-principles calculations with the generalized gradient approximation and more advanced hybrid functional, we have investigated the struc...

Although still having certain limitations, the numerical simulation technology has been increasingly applied to aid in optimizing the aluminum extrusion process and die design. In the present research, numerical simulations of the profiles extrusion process were performed, using the Finite Volume Method (FVM) and Finite Element Method (FEM) to make...

We have carried out a first-principles study on the nucleation and early-stage growth of He bubbles in Fe. The energetics, atomic and electronic structure of He-vacancy complexes, involving both a monovacancy and a nine-vacancy cluster, are examined. Based on the energetics, we then perform thermodynamics analysis to gain deeper insights into He bu...

Rare earth doping is an important approach to improve the desired properties of high-k gate dielectric oxides. We have carried out a comprehensive theoretical investigation on the phase stability, band gap, formation of oxygen vacancies, and dielectric properties for the Gd-doped HfO2. Our calculated results indicate that the tetragonal phase is mo...

The structural, electronic, and optical properties of GaInO3 have been studied by first-principles calculations based on Heyd-Scuseria-Ernzerhof hybrid functional theory. The optical properties, including the optical reflectivity, refractive index, extinction coefficient, absorption coefficient, and electron energy loss are discussed for radiation...

In the present work, we have investigated the interface of Ag (1 0 0) thin films epitaxially grown on the MgO (1 0 0) substrate by using three distinct functionals: the conventional GGA and LDA functionals, and the recently developed non-local vdW-DF functional. The vdW-DF functional can successfully repeat both the structural and energetically det...

An atomistic study has been carried out to understand plastic deformation in Mg-Al alloys. We investigate the possible plastic deformation mechanisms of intermetallic beta-Mg17Al12 which is a key precipitate phase in Mg-Al alloys. Based on the analysis of the generalized stacking fault energy, we predict the preferential slip systems in this phase...

First-principles calculations were carried out to investigate the effect of Cr on segregation of multiple H atoms in the Σ3 (1 1 1) grain boundary in bcc Fe. In the absence of Cr, four H atoms can be trapped at the interstitial site of the Fe grain boundary (areal density: 28 nm-2), and no H2 molecules are formed. The presence of Cr, however, suppr...

The influence of Mn concentration on the electronic and magnetic properties of Mn doped β-Ge3N4β-Ge3N4 was investigated by using first-principles calculations based on density functional theory. Our results show that Mn atoms prefer occupying Ge sites and have a tendency to cluster. The electronic and magnetic properties of the system with Mn dopin...

We have calculated the ground state electronic structure of He under pressure from 0 to 1500 GPa using both all-electron full-potential and pseudopotential methods based on the density functional theory (DFT). We find that throughout this pressure range, pseudopotentials yield essentially the same energy-volume curve for all of bcc, fcc, and hcp co...

Precipitates often play key roles in improving the mechanical performance of structural materials. Using first-principles density functional theory method, we have calculated the geometry and energetics of small Xn and XnHe (X = Cu, V, and Ta) clusters in bcc Fe matrix to investigate the effect of He on X precipitation on the initial stage in neutr...

Our first-principles study on the structural and electronic properties of Al-doped α-Si3N4 predict a significant band-gap narrowing, which makes this material a more efficient phosphor. Strong attraction of substitutional and interstitial Al atoms leads to the formation of stable (3+1) complexes that behave as isoelectronic traps. The near-mid-gap...

We report a first-principles density functional theory study on the role of grain boundary and dislocation loop in H blistering in W. At low temperature, the {\Sugma}3(111) tilt grain boundary, when combined with a vacancy of vanishing formation energy, can trap up to nine H atoms per (1x1) unit in (111) plane. This amount of H weakens the cohesion...

Lattice distortion induced by high concentration of H is believed to be precursor of H blistering in single crystalline W (SCW) during H isotope irradiation. However, the critical H concentration needed to trigger bond-breaking of metal atoms presents a challenge to measure. Using density functional theory, we have calculated the formation energy o...

Using ab initio density functional theory calculations, we have investigated the influence of Mo, V and Pd on the H-induced grain boundary embrittlement in Fe. We find that, in the high impurity concentration systems, all of the three alloying elements facilitate H embrittlement at the Σ3 (111) grain boundary in Fe. The calculated binary effects o...

Both helium and hydrogen are known to degrade the mechanical performance of reactor materials, but their binary effect has not been well understood. Using abinitio density functional theory calculations, we have investigated the He–H interactions both in the bulk and at the grain boundary in bcc Fe. We find an attraction of 0.56eV between one subst...

Using first-principles density functional theory method, we have investigated the distribution and magnetism of doped Mn atoms in the vicinity of the Σ3 (112) grain boundary in Ge. We find that at low concentration, the substitutional sites are energetically favorable over the interstitial ones for Mn. The binding energy of Mn varies with lattice s...