| 1. |
- He, Shuang, et al.
(författare)
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First-principles study of Re-W interactions and their effects on the mechanical properties of γ/γ' interface in Ni-based single-crystal alloys
- 2023
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Ingår i: Materials Today Communications. - : Elsevier. - 2352-4928. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of solutes and their interactions play a crucial role in determining the mechanical properties of the γ/γ′ interface in Ni-based single-crystal alloys. In this study, atomic interactions between Re and W and their alloying effects on the inter-phase cohesion of the γ/γ′ interface are investigated by first-principles calculations. Our results show that W atom exhibits a preference for partitioning into the γ phase, while the stability of the γ/γ′ interface can be enhanced due to the partitioning of W to the γ′ phase. Moreover, our results reveal that partitioned W atoms in the γ′ phase contribute to the strengthening of the γ/γ′ interface. Conversely, the dissolution of W atoms in the γ phase weakens the inter-phase cohesion. However, this detrimental effect can be mitigated by introducing of Re into the γ/γ′ interface. Partitioning of Re and W into separate phases yields minimal alterations in interaction energies, resulting in a notable enhancement of inter-phase cohesion when compared to the partitioning of Re and W within γ phase of the γ/γ′ interface. Additionally, the partitioning of solute atoms at the γ/γ′ interface leads to local lattice distortion and interfacial energy reduction, which contribute to the enhancement of inter-phase cohesion of the γ/γ′ interface. As a result, a model is proposed for interpretation of crack propagation at the γ/γ′ interface at the threshold region with the presence of tensile stress in Ni-based single-crystal alloys.
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| 2. |
- Liu, Ye, et al.
(författare)
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First-principles investigation on the thermodynamic and mechanical properties of Y4Zr3O12 and Y2Ti2O7 oxides in ferritic alloy under helium environment
- 2024
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Ingår i: Journal of Materials Research and Technology. - : Elsevier. - 2238-7854. ; 29, s. 1872-1886
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the thermodynamic and mechanical properties of Y4Zr3O12 and Y2Ti2O7 oxides in ferritic alloys with and without Helium utilizing a systematic first-principles approach. Firstly, the atomic arrangement of Y and Zr atoms at cation 18f sites in δ-(Y–Zr–O) oxide is identified, while it is found that Y4Zr3O12 exhibits a more robust formation tendency than Y2Ti2O7. Furthermore, it is noted that both Y4Zr3O12 and Y2Ti2O7 oxides demonstrate a prior ability to trap Helium compared to the bcc-Fe matrix, which leads to a substantial enhancement on the stiffness of both oxides. The elastic moduli of both Y4Zr3O12 and Y2Ti2O7 oxide exhibit a gradual increase with the growing Helium concentration. As a result, the enhanced shear modulus of oxides and sustained shear modulus of the bcc-Fe matrix collectively contribute to the overall strength of ferritic alloys under Helium environments. The findings in this work propose valuable insights for guiding critical strategies in the design of high-performance oxide-dispersion-strengthened ferritic alloys, particularly for applications in Helium environments.
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| 3. |
- Tan, Qiankun, et al.
(författare)
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Hydrogen-enhanced decohesion mechanism of the Ni-Ni3X interfaces in precipitation-hardened Ni-based alloys
- 2023
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Ingår i: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 963
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Tidskriftsartikel (refereegranskat)abstract
- Ni and its alloys are susceptible to hydrogen embrittlement. In this study, we investigate the phenomenon of hydrogen-enhanced decohesion at inter-phase interfaces in precipitation-hardened Ni-based alloys using a systematic first-principles approach. We demonstrate that hydrogen atoms primarily prefer to localize at the Ni3Al phase in the Ni/Ni3Al interface, while they tend to be trapped by Ni in the Ni/Ni3Nb interface. Our findings reveal that hydrogen induces inter-phase embrittlement in both the Ni/Ni3Al and Ni/Ni3Nb interfaces. Moreover, we show that the hydrogen-enhanced decohesion at these interfaces is influenced by various factors such as hydrogen pressure, hydrogen content, temperature, and strain. Finally, we discuss in detail the hydrogen-enhanced decohesion mechanisms at the Ni/Ni3Al and Ni/Ni3Nb interfaces, including their electronic structures, energy landscape of hydrogen at trapping sites, and schematics of crack propagation.
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