Atomic structure and adhesion of the Nb(001)/α-Nb5Si3(001) interface: a first-principles study

Shang, Jia‐Xiang; Guan, Kun Liang; Wang, Fu-He

doi:10.1088/0953-8984/22/8/085004

Cited by 27 publications

(12 citation statements)

References 44 publications

(67 reference statements)

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“…A study of a Nb (001) /αNb 5 Si 3(001) interface using a first-principles calculation showed that some of the Nb atoms at the interface become a part of Nb 5 Si 3 , and that the Nb–Si bonds at the interface are the likely sites for micro-cracking [ 71 ]. This study reported that the work of adhesion and fracture energy of the Nb (001) /αNb 5 Si 3(001) interface were 4.4 J/m 2 and 33.7 J/m 2 , respectively.…”

Section: Resultsmentioning

confidence: 99%

Alloying and Hardness of Eutectics with Nbss and Nb5Si3 in Nb-silicide Based Alloys

Tsakiropoulos

2018

Materials

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In Nb-silicide based alloys, eutectics can form that contain the Nbss and Nb5Si3 phases. The Nb5Si3 can be rich or poor in Ti, the Nb can be substituted with other transition and refractory metals, and the Si can be substituted with simple metal and metalloid elements. For the production of directionally solidified in situ composites of multi-element Nb-silicide based alloys, data about eutectics with Nbss and Nb5Si3 is essential. In this paper, the alloying behaviour of eutectics observed in Nb-silicide based alloys was studied using the parameters ΔHmix, ΔSmix, VEC (valence electron concentration), δ (related to atomic size), Δχ (related to electronegativity), and Ω (= Tm ΔSmix/|ΔHmix|). The values of these parameters were in the ranges −41.9 < ΔHmix <−25.5 kJ/mol, 4.7 < ΔSmix < 15 J/molK, 4.33 < VEC < 4.89, 6.23 < δ < 9.44, 0.38 < Ω < 1.35, and 0.118 < Δχ < 0.248, with a gap in Δχ values between 0.164 and 0.181. Correlations between ΔSmix, Ω, ΔSmix, and VEC were found for all of the eutectics. The correlation between ΔHmix and δ for the eutectics was the same as that of the Nbss, with more negative ΔHmix for the former. The δ versus Δχ map separated the Ti-rich eutectics from the Ti-poor eutectics, with a gap in Δχ values between 0.164 and 0.181, which is within the Δχ gap of the Nbss. Eutectics were separated according to alloying additions in the Δχ versus VEC, Δχ versus , δ versus , and VEC versus maps, where = Al + Ge + Si + Sn. Convergence of data in maps occurred at δ ≈ 9.25, VEC ≈ 4.35, Δχ in the range ≈ 0.155 to 0.162, and in the range ≈ 21.6 at.% to ≈ 24.3 at.%. The convergence of data also indicated that the minimum concentration of Ti and maximum concentrations of Al and Si in the eutectic were about 8.7 at.% Ti, 6.3 at.% Al, and 21.6 at.% Si, respectively, and that the minimum concentration of Si in the eutectic was in the range 8 < Si < 10 at.%.

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Section: Resultsmentioning

confidence: 99%

Alloying and Hardness of Eutectics with Nbss and Nb5Si3 in Nb-silicide Based Alloys

Tsakiropoulos

2018

Materials

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“…The former would be expected to affect the strength of the NbeSi bond compared with the NbeNb bond or NbeTM/RM bond. A recent study has shown that NbeSi bonds are weaker than NbeNb bonds [28]. One motivation for the present work was to explore the role of Mo and W on the chemistry of the Nb ss in the presence/ absence of Hf and to compare with the effect of the synergy of Mo, Ta and Hf.…”

Section: Introductionmentioning

confidence: 99%

“…In the a, b and g forms of Nb 5 Si 3 bonding is dominantly covalent. The unit cell of aNb 5 Si 3 consists of atomic layers some of which are more closely packed and others less closely packed [28]. Substitution is possible in Nb and Si atoms in either type of closely packed layers.…”

Section: Introductionmentioning

confidence: 99%

Study of the role of Hf, Mo and W additions in the microstructure of Nb–20Si silicide based alloys

Grammenos

Tsakiropoulos

2011

Intermetallics

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“…Generally, the coherent interface approximation [22] is applied to study the interfaces in which the misfit dislocation is ignored. The coherent interfaces have been investigated by many researchers [23][24][25][26][27][28][29][30][31]; whereas, the obtained theoretical work of adhesion is larger than the observed values [32].…”

Section: Introductionmentioning

confidence: 99%

The Adhesive Properties of Coherent and Semicoherent NiAl/V Interfaces Within the Peierls-Nabarro Model

Linghu

Wang

et al. 2016

Crystals

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Abstract:The work of adhesion and the interface energy of NiAl/V coherent interface systems have been investigated using first-principles methods. The adhesion of the Ni-terminated interface is larger than the Al-terminated interface. The difference in charge density and the density of states show that the Ni-terminated interface is dominated by metallic bonds, and the Al-terminated interface is dominated by metallic and covalent bonds. To account for the effects of misfit dislocations on the semicoherent interfaces, the Peierls-Nabarro model combined with generalized stacking fault energy is employed to determine the interface energy. It is found that misfit dislocations can reduce the adhesion of the interface, and the reduction increases with the maximum of the restoring force.

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Atomic structure and adhesion of the Nb(001)/α-Nb₅Si₃(001) interface: a first-principles study

Cited by 27 publications

References 44 publications

Alloying and Hardness of Eutectics with Nbss and Nb5Si3 in Nb-silicide Based Alloys

Alloying and Hardness of Eutectics with Nbss and Nb5Si3 in Nb-silicide Based Alloys

Study of the role of Hf, Mo and W additions in the microstructure of Nb–20Si silicide based alloys

The Adhesive Properties of Coherent and Semicoherent NiAl/V Interfaces Within the Peierls-Nabarro Model

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