@article{Xu2023, 
author = {Huidong Xu and Longfei Jiang and Ke Chen and Qing Huang and Xiaobing Zhou},
title = {High-entropy rare-earth diborodicarbide: A novel class of high-entropy (Y0.25Yb0.25Dy0.25Er0.25)B2C2 ceramics},
year = {2023},
journal = {Journal of Advanced Ceramics},
volume = {12},
number = {7},
pages = {1430-1440},
keywords = {high-entropy rare-earth diboridcarbide, (Y0.25Yb0.25Dy0.25Er0.25)B2C2 (REB2C2), high-entropy ceramics (HECs), thermal property, damage tolerance},
url = {https://www.sciopen.com/article/10.26599/JAC.2023.9220765},
doi = {10.26599/JAC.2023.9220765},
abstract = {A novel class of high-entropy rare-earth metal diborodicarbide (Y0.25Yb0.25Dy0.25Er0.25)B2C2 (HE-REB2C2) ceramics was successfully fabricated using the in-situ reactive spark plasma sintering (SPS) technology for the first time. Single solid solution with a typical tetragonal structure was formed, having a homogeneous distribution of four rare-earth elements, such as Y, Yb, Dy, and Er. Coefficients of thermal expansion (CTEs) along the a and c directions (αa and αc) were determined to be 4.18 and 16.06 μK−1, respectively. Thermal expansion anisotropy of the as-obtained HE-REB2C2 was attributed to anisotropy of the crystal structure of HE-REB2C2. The thermal conductivity (k) of HE-REB2C2 was 9.2±0.09 W·m−1·K−1, which was lower than that of YB2C2 (19.2±0.07 W·m−1·K−1), DyB2C2 (11.9±0.06 W·m−1·K−1), and ErB2C2 (12.1±0.03 W·m−1·K−1), due to high-entropy effect and sluggish diffusion effect of high-entropy ceramics (HECs). Furthermore, Vickers hardness of HE-REB2C2 was slightly higher than that of REB2C2 owing to the solid solution hardening mechanism of HECs. Typical nano-laminated fracture morphologies, such as kink boundaries, delamination, and slipping were observed at the tip of Vickers indents, suggesting ductile behavior of HE-REB2C2. This newly investigated class of ductile HE-REB2C2 ceramics expanded the family of HECs to diboridcarbide compounds, which can lead to more research works on high-entropy rare-earth diboridcarbides in the near future.}
}