著者

Yoichi Ikeda Yoshihiko Umemoto Daiju Matsumura Takuya Tsuji Yuki Hashimoto Takafumi Kitazawa Masaki Fujita

出版者

The Japan Institute of Metals and Materials

雑誌

MATERIALS TRANSACTIONS (ISSN:13459678)

巻号頁・発行日

vol.64, no.9, pp.2254-2260, 2023-09-01 (Released:2023-08-25)

参考文献数

29

被引用文献数

1

---

Extended X-ray absorption fine structure (EXAFS) and neutron diffraction experiments were carried out to clarify the typical features of the local structure of a family of medium-entropy alloys (CrCoNi, MnCoNi, and FeCoNi). A simple random cluster model was constructed for analyzing EXAFS spectra, and static and dynamic components of the mean-square relative displacement (MSRD) were separately extracted. In our analysis, the static MSRD of the MnCoNi sample was slightly larger than those of the CrCoNi and FeCoNi samples, whereas the dynamic MSRDs of these samples were almost identical. Based on the complementary neutron diffraction data, we argued that the origin of the large static displacement in the MnCoNi alloy can be associated with a short-range structural transformation through long-term structural relaxation.

著者

Yoshihiko Umemoto Yoichi Ikeda Masaki Fujita

出版者

The Japan Institute of Metals and Materials

雑誌

MATERIALS TRANSACTIONS (ISSN:13459678)

巻号頁・発行日

vol.64, no.8, pp.2018-2021, 2023-08-01 (Released:2023-07-25)

参考文献数

24

被引用文献数

3

---

Neutron scattering experiments were conducted to reveal the origin of diffuse scattering in a medium-entropy alloy (MnCoNi). Results showed that a time-temperature-dependent short- and long-range structural transformation from a face-centered cubic to a primitive tetragonal structure occurs. In the MnCoNi alloy, the long-range ordered phase with a relatively small c/a ratio of 3.7(1)% can only be grown in a limited temperature range, whereas short-range structural transformation with a short correlation length of 1–4 nm can be formed in a wide temperature range. On the contrary, no sign of short-/long-range staggered atomic rearrangement, such as L10 and L12 structures, was observed in the CrCoNi alloy at least at room temperature. The difference in the forming ability of short-/long-range ordering between the MnCoNi and CrCoNi alloys was discussed.