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<p>This study explored the influence of 2 at% Ti elements addition on the microstructure evolution and compressive creep performance of Haynes 244 (Ni-8Cr-6W-22.5Mo) at 650&#xa0;°C under 80 ~ 180&#xa0;MPa stress states. The results indicate that trace addition of Ti can promote the simultaneous formation of C11<sub>b</sub>-type&#xa0;and D0<sub>22</sub>-type&#xa0;long-range-ordered superlattice&#xa0;phases after aging treatment at 650&#xa0;°C for 120&#xa0;h. The aged Ti-doped alloy has better creep resistance at 650&#xa0;°C /80&#xa0;MPa, and the steady-state creep rate is only 9.17 <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\times\)</EquationSource> <EquationSource Format="MATHML"><math> <mo>×</mo> </math></EquationSource> </InlineEquation> 10<sup>-8</sup>&#xa0;s<sup>-1</sup>. Under the coupled influence of stress and high temperature, the existence of nanoscale superlattices is also observed after creep in the as-solid alloy. The stress exponent values of Haynes 244 and the Ti-doped alloys at 650&#xa0;°C are 5.10 and 5.96, respectively, indicating that the dislocation climbing dominated the creep mechanism. The ordering mechanism of C11<sub>b</sub>&#xa0;and D0<sub>22</sub> superlattices is continuous ordering, and the interface between precipitates and matrix is coherent. These results indicate that Haynes 244 with Ti addition synergistically precipitates nanoscaled C11<sub>b</sub>&#xa0;and D0<sub>22</sub> superlattices uniformly dispersed in the matrix, which can effectively pin the dislocation movement, achieve good coherency strengthening and precipitation strengthening, and thus improve creep resistance.</p>

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Effect of Ti Microalloying on the Creep Behavior of Ni-Cr-Mo-Based High-Temperature Alloy

  • 期刊论文

  • 发表日期：

    2025年9月22日

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  • Jingyi Song,
  • Shumin Chen,
  • Xiaolin Li,
  • Yating Li,
  • Yi He,
  • Xiangyu Gao,
  • Haifeng Wang

摘要

This study explored the influence of 2 at% Ti elements addition on the microstructure evolution and compressive creep performance of Haynes 244 (Ni-8Cr-6W-22.5Mo) at 650 °C under 80 ~ 180 MPa stress states. The results indicate that trace addition of Ti can promote the simultaneous formation of C11b-type and D022-type long-range-ordered superlattice phases after aging treatment at 650 °C for 120 h. The aged Ti-doped alloy has better creep resistance at 650 °C /80 MPa, and the steady-state creep rate is only 9.17 \(\times\) × 10-8 s-1. Under the coupled influence of stress and high temperature, the existence of nanoscale superlattices is also observed after creep in the as-solid alloy. The stress exponent values of Haynes 244 and the Ti-doped alloys at 650 °C are 5.10 and 5.96, respectively, indicating that the dislocation climbing dominated the creep mechanism. The ordering mechanism of C11b and D022 superlattices is continuous ordering, and the interface between precipitates and matrix is coherent. These results indicate that Haynes 244 with Ti addition synergistically precipitates nanoscaled C11b and D022 superlattices uniformly dispersed in the matrix, which can effectively pin the dislocation movement, achieve good coherency strengthening and precipitation strengthening, and thus improve creep resistance.