First-principles calculation of W/WC interface: Atomic structure, stability and electronic properties

Jin, Na; Yang, Yanqing; X, Luo; Shuai, Liu; Zhang, Xiao; Guo, Pengfei; Huang, Bin

doi:10.1016/j.apsusc.2014.10.119

Cited by 44 publications

(3 citation statements)

References 32 publications

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“…2f) shows that the interfacial Mg atomic position in the B-terminated center-site interface is very close to Zr atoms of bulk ZrB 2 , and this correspondingly results in the increased W ad . This phenomenon also occurs in SiC/Ti [41], W/WC [42] and SiC/TiC [43] interfaces. Overall, after geometry optimization, the Zr-terminated top-, center-and bridge-site interfaces transform into the "new" center-site interfaces which almost have the same properties such as the atomic structure, interface distance d int , bond length d bond and ideal work of adhesion W ad .…”

Section: Work Of Adhesion and Int Erfacial Energymentioning

confidence: 74%

First-principles study on the stability and electronic structure of Mg/ZrB2 interfaces

Hui

Dong-Yuan

et al. 2016

Sci. China Mater.

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ratio, high stiffness, high damping capacity, good elastic modulus, good castability and unique biodegradability in the physiological environment [1][2][3][4]. However, their applications are limited by the poor high-temperature strength and creep resistance.To improve the strength of magnesium alloy, it is a reliable way to refine the grain size using effective nucleants during the casting process. ZrB 2 nanoparticle are such effective nucleants and they are capable of inducing finer long-period stacking ordered phase (nano-LPSO-layer) formation due to the nano-surface effect and finally resulting in the formation of nanograins in magnesium alloys [5]. Also, it is a suitable way to improve the magnesium alloys' stiffness, elastic modulus and wear resistances by preparing particle reinforced magnesium matrix composites since ceramic particles have high strength, hardness and high-wearing features [6,7]. Compared with SiC and TiC particles, ZrB 2 particle reinforced magnesium-based composites fabricated by a direct melt-mixing method [8] have the best strength [9]. The stress transfers from Mg matrix to ZrB 2 reinforcement through the ZrB 2 /Mg interface, and the micro-hardness, fatigue resistance and friction factor of the composites are directly affected by interface bonding [10,11].Up to now, it is known that for effective heterogeneous nucleants in magnesium melt or effective reinforcements in particle reinforced magnesium matrix composites, the lattice mismatch and the chemical interaction play important roles in the overall interfacial energy [12]. And, the ZrB 2 /Mg interface will seriously influence the nucleating in Mg melt [5] or the strength of the composites [13]. Hence, the main purpose of this work was to investigate the mechanism of interface bonding of Mg/ZrB 2 in atomic level and help to improve the mechanical properties of the material.First-principles calculation is a powerful method to provide fundamental information at atomic or electronic level. Generally, (001) plane is a stable low index plane for

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Section: Work Of Adhesion and Int Erfacial Energymentioning

confidence: 74%

First-principles study on the stability and electronic structure of Mg/ZrB2 interfaces

Hui

Dong-Yuan

et al. 2016

Sci. China Mater.

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“…For compound systems, surface characteristics vary with different terminations even for the same index surface [53,54]. We found that the evaluated low-index WB, WB 2 and W 2 B surfaces terminated with single element layers can be identified by the index and elements on the top two surface layers except for W 2 B(001), and thus, W x B y (hkl)-T ij or W x B y (hklm)-T ij is used to represent a surface with terminated elements i and j, where h, k, l and m are Miller-indices, and the i and j correspond to the element on the first and second surface layer, respectively.…”

Section: Methodsmentioning

confidence: 99%

Surface stability and H adsorption and diffusion near surfaces of W borides: a first-principles study

Wirth

2023

Nucl. Fusion

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Understanding the behavior of tungsten boride (WxBy) surfaces in a fusion reactor environment is an important topic since boronization is a common wall conditioning method used in fusion Tokamaks. We report the results of density functional theory (DFT) calculations that investigate the surface stability of WxBy (tetragonal I41/amd-WB, hexagonal P63/mmc-WB2 and tetragonal I4/m-W2B) with low-index orientations, as well as hydrogen (H) energetics near WxBy surfaces. For single element terminated WxBy surfaces, B terminated surfaces are more energetically stable than W terminated as a result of significant reconstruction of B. The H surface adsorption energy and activation energy of H diffusion penetration below WxBy surfaces are mainly related to the outer termination. Specifically, the WB(001) surface terminated with two B layers, referred to as WB(001)-TBB, has higher H adsorption affinity and lower H diffusivity on this surface than other terminations, which is controlled by the significant charge transfer from B to H. However, B atoms on the WB2(0001)-TBB surface decrease both H adsorption and diffusivity on the surface, but enhance H diffusion below the surface in comparison to W terminated WB2(0001) surface. H would be trapped and diffuse within atomic surface gaps on the WB2(2-1-10) surface, while H below the surface layer would jump along the [0001] direction rather than diffuse into bulk. The surface diffusion activation energy of H on the W2B(001) surface slightly varies with terminations. Once H crosses the surface layer of W2B(001) with either termination, it prefers to diffuse into the bulk, or back towards the surface, rather than move parallel to the surface. Interestingly, WB2(0001) and WB2(2-1-10) surfaces will have relatively higher H retention than the other WxBy surfaces evaluated in this work.

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“…An important part of such an investigation is an understanding of the interfaces that can be expected to form in the WC/W interface boundaries in this contact, to know which specific interfaces to choose, or to know how a specific interface compares to the larger trends present in the system. Studies of WC/W interfaces have been made but have been limited to individual interfaces , making predictions or general statements regarding this system difficult as there is no information on which interfaces actually form and results can be expected to vary depending on which ones are chosen. WC has a hexagonal structure with the most common surfaces being terminated either by the basal [0001] or prismatic [101̅0] planes; , additionally, the prismatic terminations can be of two different types where type-I has a final interplanar distance half the length of type-II .…”

Section: Introductionmentioning

confidence: 99%

Large-Scale Screening of Interface Parameters in the WC/W System Using Classical Force Field and First-Principles Calculations

et al. 2021

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To understand the observed wear in WC/Co tools during machining of Ti-alloys, it is important to know which interfaces are present in the tool-workpiece contact zone. It has been shown that WC grains in contact with the workpiece form a C depleted layer consisting of BCC W, and as such, knowledge of which WC/W interfaces can be expected and which interfaces can be used as starting points for further computations are of great importance. Here, this is studied by the systematic construction of interfaces and evaluation of the work of adhesion and interfacial energies of 60,000 unique interfaces spread across six different interface systems made up of the basal and prismatic surfaces of WC and the low index surfaces of BCC W. Calculations are made using a classical approach in LAMMPS as well as subset analysis using first principles in VASP (Vienna Ab Initio Simulation Package). The results show trends as functions of strain and system size giving a large-scale overview of this system and finding the energetically preferred interface combination to be the type-I, Wterminated prismatic WC surface against the [110] surface of BCC W.

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First-principles calculation of W/WC interface: Atomic structure, stability and electronic properties

Cited by 44 publications

References 32 publications

First-principles study on the stability and electronic structure of Mg/ZrB2 interfaces

First-principles study on the stability and electronic structure of Mg/ZrB2 interfaces

Surface stability and H adsorption and diffusion near surfaces of W borides: a first-principles study

Large-Scale Screening of Interface Parameters in the WC/W System Using Classical Force Field and First-Principles Calculations

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