材料科学与技术 ›› 2023, Vol. 165 ›› Issue (0): 143-152.DOI: 10.1016/j.jmst.2023.04.058

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  • 收稿日期:2022-12-10 修回日期:2023-04-24 接受日期:2023-04-24 出版日期:2023-12-01 发布日期:2023-06-10

Effect of short-range order on the high-temperature plastic deformation behavior of Ni-Cr-W, Ni-W, and Ni-Re single crystals

Koji Hagiharaa,b,*   

  1. aDepartment of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso, Nagoya, Aichi 466-8555, Japan;
    bDivision of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
  • Received:2022-12-10 Revised:2023-04-24 Accepted:2023-04-24 Online:2023-12-01 Published:2023-06-10
  • Contact: *Department of Physical Science and Engineering, Nagoya In- stitute of Technology, Gokiso, Nagoya, Aichi 466-8555, Japan. E-mail address: hagihara@nitech.ac.jp

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Abstract: The development of a Ni-based superalloy that consists of only the γ-solid-solution phase is highly desired for some applications such as high-temperature gas-cooled reactors in power plants. In this study, the temperature dependence of the plastic deformation behavior of Ni-22Cr-8W (at%) alloy was examined for the first time by using a single crystal, focusing on the influence of the short-range order (SRO), especially upon high-temperature deformation behavior. The critical resolved shear stress (CRSS) for (111)[10$\bar{1}$] slip exhibited a rapid decrease as the temperature increased at low temperatures but an almost constant value of ∼45 MPa between 500 and 900 °C. In addition, a slight yield stress anomaly (YSA) was observed, reaching a maximum value at 1000 °C.
To clarify the influence of the SRO on the YSA behavior, the mechanical properties of Ni-8W and Ni-5Re single crystals were also examined. Similar temperature dependence for the CRSS, including the occurrence of slight YSA, was observed for Ni-8W, in which SRO developed. In the Ni-5Re single crystal in which SRO did not significantly develop, however, the CRSS monotonically decreased as the temperature increased. The results suggest that the presence of SRO in a Ni-Cr-W alloy contributes to the strengthening of the alloy not only at low temperatures but also at high temperatures up to ∼1000 °C. The results strongly suggested that the pseudo-PLC effect is related to the origin of YSA appearing in Ni-based γ-solid-solution alloys at high temperatures.

Key words: Ni-based superalloy, Short-range order (SRO), Dislocation, Yield stress anomaly (YSA)