Role of hydrogen on the structural stability, mechanical and thermodynamic properties of the cubic TM3Si silicides

https://doi.org/10.1016/j.ijhydene.2021.06.038Get rights and content

Highlights

  • Hydrogenation mechanism of TM3Si silicides is studied by first-principles calculations.

  • We find that hydrogen is a thermodynamic stability in TM3Si silicides.

  • The hydrogen weakens the elastic moduli and hardness of TM3Si silicides.

  • The hydrogen weakens the Debye temperature of TM3Si silicides.

Abstract

Although the TM3Si silicides play an important role in transition metal silicides high-temperature materials, the hydrogenated mechanism of the cubic TM3Si is entirely unclear. To explore the hydrogenated mechanism, in this work, we apply the first-principles calculations to study the influence of hydrogen on the structural stability, mechanical and thermodynamic properties of TM3Si silicides. Based on the structural characteristic, four TM3Si silicides (Mo3Si, Nb3Si, Cr3Si and W3Si) and three hydrogen occupied models were considered. In particular, the influence of hydrogen on the stability, elastic properties, hardness, brittle-or-ductile behavior and Debye temperature of TM3Si was investigated. The result shows that the hydrogen is a thermodynamic stability in TM3Si because of the electronic interaction between hydrogen and TM3Si silicides. The thermodynamic stability of the hydrogenated TM3Si follows the order of Nb3Si<Cr3Si<Mo3Si<W3Si. Importantly, it is found that the hydrogen weakens the elastic properties and hardness of TM3Si because the introduction of hydrogen reduces the electronic interaction between TM atom and Si atom. On the contrary, the hydrogen improves the ductile behavior of TM3Si silicides. In addition, the hydrogen reduces the Debye temperature of TM3Si silicides.

Introduction

The development of high-temperature material is still a big challenge for the future application in aeronautics and astronautics industries [[1], [2], [3], [4], [5], [6], [7], [8], [9], [10]]. However, the diffusion of hydrogen (H or H2) under high-temperature environment weakens the interaction between atoms in high-temperature materials and reduces the energy necessary for crack propagation in a system [11]. As a result, the formation of crack by the critical concentration of hydrogen results in hydrogen embrittlement (HE) [12]. Therefore, the improvement of the resistance against hydrogen embrittlement is a big challenge for the applications of high-temperature materials.

Among these high-temperature materials, the transition metal silicides (TMSis) are promising high-temperature structural materials compared to the conventional Ni-based superalloys or the other intermetallics [[13], [14], [15], [16]]. Compared to the Ni-based superalloys, the measured ultimate tensile strength of the Nb5Si3–Nb3Si composite is 413 MPa at room temperature and 496 MPa at high temperature (~1200 °C) [17]. The measured melting point of MoSi2 is up to 2030 °C, which is potentially used in high-temperature applications [18]. In particular, these transition metal silicides not only show high mechanical properties but also exhibit better oxidation resistance under high temperature environment [[19], [20], [21], [22]]. For example, the additive Hf in Nb-based silicide shows better oxidation resistance at the temperature of 1250 °C, while the measured hardness of Nb-based silicide increases with increasing Hf concentration [23]. However, the brittle fracture of transition metal (TM) silicides such as TMSi2 or TM5Si3 limits their high-temperature applications [[24], [25], [26]]. The published literatures have shown that the transition metal binary silicides have three phases: TMSi2, TM3Si and TM5Si3 [27,28]. Our previous work has also found that the cubic TM3Si has better ductility due to the symmetrical TM-Si bonds [29]. It is further found that the mechanical properties of some TM3Si are also stronger than the TM5Si3. Here, the calculated bulk modulus and shear modulus of W3Si are 278 GPa and 139 GPa [29], respectively, which are larger than the corresponding bulk modulus and shear modulus for W5Si3. Importantly, the previous studies have shown that the TM3Si is an intermediate phase, which is formed under high-temperature. As a result, the intermediate phase also influences the overall properties (mechanical properties and oxidation resistance) of the transition metal silicides under high-temperature environment. Therefore, it is necessary to reveal the hydrogen embrittlement of TM3Si silicides. Unfortunately, the mechanism of hydrogen embrittlement for TM3Si is entirely unknown.

To solve the problem, we apply the first-principles calculations to study the mechanism of hydrogen embrittlement of TM3Si silicides. From the published works, we select four important TM3Si silicides: Mo3Si, Cr3Si, Nb3Si and W3Si. Based on the structural feature, three hydrogen (H)-doped sites: H (1), H (2) and H (3) are designed. Importantly, the influence hydrogen on the elastic properties, hardness, brittle-or-ductile behavior and Debye temperature of TM3Si silicides is further studied. The nature of hydrogen embrittlement of TM3Si is analyzed by the electronic structure. This work shows that the hydrogen is a thermodynamic stability in TM3Si silicides. In particular, the hydrogen will decrease elastic properties, Vickers hardness and Debye temperature of TM3Si silicides.

Section snippets

Theoretical methods

From the previous published literature, the TM3Si silicide is a derived cubic phase (Pm-3m, No.223), while the lattice parameter is a = 4.8921 Å for Mo3Si [30], a = 4.564 Å for Cr3Si [31], a = 5.120 Å for Nb3Si [32] and a = 4.910 Å for W3Si [33]. Compared to the AuCu3-type cubic phase, the position of TM metallic atom has small migration from (0, 0.5, 0.5) site to (0, 0.25, 0.25) site. For cubic TM3Si silicide, it is believed that the hydrogen (H) prefers to locate at the interstitial site due

Results and discussions

To explore their hydrogen embrittlement, it is necessary to examine the hydrogen stability in TM3Si silicides. Therefore, it is firstly investigated the structural stability of the H-doped TM3Si. Generally speaking, the structural stability of a solid is related to the chemical potential between atom and the near atom [[40], [41], [42], [43]]. Therefore, the stability of the H-doped TM3Si silicides is calculated by using the hydrogen doped formation energy (Ef) [[44], [45], [46], [47]], which

Conclusions

In summary, the hydrogenated mechanism of TM3Si is studied by using the first-principles calculations. Four TM3Si silicides: Mo3Si, Nb3Si, Cr3Si and W3Si are considered based on the reported work. According to the structural feature, three H-doped models: H (1), H (2) and H (3) are designed. In particular, the influence of hydrogen on the structural stability, elastic properties, hardness, brittle-or-ductile behavior and Debye temperature of TM3Si are calculated.

The results show that the

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work is supported by the State Key Laboratory of Industrial Vent Gas Reuse (No. SKLIVGR-SWPU-2020-03).

References (66)

  • C. Zenk et al.

    Low temperature deformation of MoSi2 and the effect of Ta, Nb and Al as alloying elements

    Acta Mater

    (2019)
  • S. Wang et al.

    First-principles study of the effect of Cr and Al on the oxidation resistance of WSi2

    Chem Phys Lett

    (2018)
  • Y. Pan et al.

    Insight into the oxidation mechanism of Nb3Si(111) surface: first-principles calculations

    Mater Res Bull

    (2018)
  • G.A. Yakaboylu et al.

    Chromium silicide-based composites fabricated via solid-state reactions: phase development, oxidation behavior and electrical properties at high-temperatures

    J Alloy Compd

    (2018)
  • Y. Pan et al.

    Insight into the oxidation mechanism of MoSi2: ab-initio calculations

    Ceram Int

    (2018)
  • S. Zhang et al.

    Microstructure, mechanical properties and oxidation resistance of Nb silicide based ultrahigh temperature alloys with Hf addition

    Mater Sci Eng A

    (2015)
  • Y. Pan et al.

    Influence of vacancy on the elastic properties, ductility and electronic properties of hexagonal C40 MoSi2 from first-principles calculations

    Vacuum

    (2020)
  • H. Yan et al.

    Exploration of stable stoichiometries, ground-state structures, and mechanical properties of the W-Si system

    Ceram Int

    (2020)
  • L. Liu et al.

    Microstructure and thermoelectric properties of higher manganese silicides fabricated via gas atomization and spark plasma sintering

    Mater Chem Phys

    (2020)
  • A.I. Kartamyshev et al.

    The influence of lattice vibrations and electronic free energy on phase stability of titanium silicides and Si solubility in hcp titanium: a DFT study

    Calphad

    (2019)
  • C. Wang et al.

    Oxidation behaviour of a Ge-modified silicide coating on an Nb-Si based alloy in the moderate temperature range

    Corros Sci

    (2020)
  • P.K. Ray et al.

    Effect of Nb and W substitutions on the stability of the A15 Mo3Si phase

    J Alloy Compd

    (2012)
  • R. Flukiger et al.

    Chaleur specifique et supraconductivite dans des alliages de structure A 15 a base de chrome

    J Phys Chem Solids

    (1971)
  • H. Iwasaki et al.

    A15-Nb3Si produced by high-pressure annealing of amorphous sputter deposits

    Solid State Commun

    (1982)
  • Y. Tarutani et al.

    Atomic radii and lattice parameters of the A15 crystal structure

    J Alloy Compd

    (1977)
  • Y. Pan et al.

    Influence of noble metals on the electronic and optical properties of the monoclinic ZrO2: a first-principles study

    Vacuum

    (2021)
  • D.L. Pu et al.

    Influence of high pressure on the structure, hardness and brittle-to-ductile transition of NbSi2 ceramics

    Ceram Int

    (2021)
  • Y. Pan et al.

    Sulfur vacancy enhances the electronic and optical properties of FeS2 as the high performance electrode material

    J Alloy Compd

    (2021)
  • X. Zhang et al.

    Insight into the elastic and anisotropic properties of BiMg2MO6 (M= P, as and V) ceramics from the first-principles calculations

    Ceram Int

    (2019)
  • Y. Pan et al.

    First-principles investigation of structural stability, mechanical and thermodynamic properties of Pt3Zr5 compounds

    Physica B

    (2021)
  • X. Zhang et al.

    First-principles prediction of the physical properties of ThM2Al20 (M= Ti, V, Cr) intermetallics

    Solid State Commun

    (2018)
  • Y. Pan et al.

    Influence of alloying elements on the structural stability, elastic, hardness and thermodynamic properties of Mo5SiB2 from first-principles calculations

    Ceram Int

    (2020)
  • S. Chen et al.

    Noble metal interlayer-doping enhances the catalytic activity of 2H-MoS2 from first-principles investigations

    Int J Hydrogen Energy

    (2021)
  • Cited by (65)

    View all citing articles on Scopus
    View full text