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<p>Advanced aero-engines with thrust-to-weight ratios of 15–20 require turbine blade materials (single-crystal superalloys) that can operate at temperatures of up to 1200&#xa0;°C. However, the microstructural evolution of such superalloys is dominated by γ’ phase dissolution at 1200&#xa0;°C. Here, the effect of γ’ phase dissolution on the microstructural characteristics and creep properties of superalloys at 1200&#xa0;°C was investigated. Nine experimental Ni-based superalloys containing different γ’-forming elements, including Ta and Al, were prepared. The study showed that γ’ phase dissolution decreased the strength and elastic modulus of the γ matrix and increased its effective diffusion coefficient. The yield strength increment resulted from increased resistance to dislocation shear in the γ’ phase, which was enriched by Ta and Al. Moreover, the effect of γ’ phase dissolution on the strength of the γ’ phase was negligible. The formation of rattan-shaped structures and topological inversion of the γ–γ’ phases in Al- and Ta-rich alloys were instrumental in weakening the creep properties at 1200&#xa0;°C. Finally, a creep property–microstructure control model that considers γ’ phase dissolution and excessive Ta and Al contents at 1200&#xa0;°C was established; the values calculated using this model were consistent with the experimental observations. The findings of this study promote the design or selection of superalloys suitable for ultra-high-temperature applications.</p>

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Influence Mechanism of γ’ Phase Dissolution on Microstructural Characteristics and Creep Properties of Ni-Based Single-Crystal Superalloys at 1200 °C

  • 期刊论文

  • 发表日期：

    2025年3月8日

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  • Liang Luo,
  • Longlong Di,
  • Hao Fu,
  • Yuebiao Yang,
  • Xuehai Qian,
  • Zheyu He,
  • Yimin Li,
  • Fenghua Luo

摘要

Advanced aero-engines with thrust-to-weight ratios of 15–20 require turbine blade materials (single-crystal superalloys) that can operate at temperatures of up to 1200 °C. However, the microstructural evolution of such superalloys is dominated by γ’ phase dissolution at 1200 °C. Here, the effect of γ’ phase dissolution on the microstructural characteristics and creep properties of superalloys at 1200 °C was investigated. Nine experimental Ni-based superalloys containing different γ’-forming elements, including Ta and Al, were prepared. The study showed that γ’ phase dissolution decreased the strength and elastic modulus of the γ matrix and increased its effective diffusion coefficient. The yield strength increment resulted from increased resistance to dislocation shear in the γ’ phase, which was enriched by Ta and Al. Moreover, the effect of γ’ phase dissolution on the strength of the γ’ phase was negligible. The formation of rattan-shaped structures and topological inversion of the γ–γ’ phases in Al- and Ta-rich alloys were instrumental in weakening the creep properties at 1200 °C. Finally, a creep property–microstructure control model that considers γ’ phase dissolution and excessive Ta and Al contents at 1200 °C was established; the values calculated using this model were consistent with the experimental observations. The findings of this study promote the design or selection of superalloys suitable for ultra-high-temperature applications.