TY - JOUR
T1 - Phase structure, mechanical properties and thermal properties of high-entropy diboride (Hf0.25Zr0.25Ta0.25Sc0.25)B2
AU - Zhang, Ze
AU - Zhu, Shizhen
AU - Liu, Yanbo
AU - Liu, Ling
AU - Ma, Zhuang
N1 - Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2022/10
Y1 - 2022/10
N2 - A new high-entropy diboride (Hf0.25Zr0.25Ta0.25Sc0.25)B2 was designed to investigate the effect of introducing rare-earth metal diboride ScB2 into high-entropy diborides on its structure and properties. The local mixing enthalpy predicts that (Hf0.25Zr0.25Ta0.25Sc0.25)B2 has high enthalpy driving force, which more easily allows the formation of single-phase AlB2-type structures between components. The experiments further demonstrate that (Hf0.25Zr0.25Ta0.25Sc0.25)B2 possesses excellent phase stability, lattice integrity and nanoscale chemical homogeneity. (Hf0.25Zr0.25Ta0.25Sc0.25)B2 showed relatively high hardness (30.7 GPa), elastic modulus (E, G, and B of 522, 231 and 233 GPa, respectively), bending strength (454 MPa), and low thermal conductivity (13.9 W·m−1·K−1). The thermal expansion of (Hf0.25Zr0.25Ta0.25Sc0.25)B2 is higher than that of ZrB2 and HfB2 due to weakened bonding (M d - B p and M dd bonding) and enhanced anharmonic effects. Thus, incorporating Sc into high-entropy diborides can tailor the properties associated with the bonding, which further expands the compositional space of high-entropy diborides.
AB - A new high-entropy diboride (Hf0.25Zr0.25Ta0.25Sc0.25)B2 was designed to investigate the effect of introducing rare-earth metal diboride ScB2 into high-entropy diborides on its structure and properties. The local mixing enthalpy predicts that (Hf0.25Zr0.25Ta0.25Sc0.25)B2 has high enthalpy driving force, which more easily allows the formation of single-phase AlB2-type structures between components. The experiments further demonstrate that (Hf0.25Zr0.25Ta0.25Sc0.25)B2 possesses excellent phase stability, lattice integrity and nanoscale chemical homogeneity. (Hf0.25Zr0.25Ta0.25Sc0.25)B2 showed relatively high hardness (30.7 GPa), elastic modulus (E, G, and B of 522, 231 and 233 GPa, respectively), bending strength (454 MPa), and low thermal conductivity (13.9 W·m−1·K−1). The thermal expansion of (Hf0.25Zr0.25Ta0.25Sc0.25)B2 is higher than that of ZrB2 and HfB2 due to weakened bonding (M d - B p and M dd bonding) and enhanced anharmonic effects. Thus, incorporating Sc into high-entropy diborides can tailor the properties associated with the bonding, which further expands the compositional space of high-entropy diborides.
KW - First-principles calculations
KW - High-entropy ceramics
KW - Mechanical properties
KW - Metal diborides
KW - Thermal properties
UR - http://www.scopus.com/inward/record.url?scp=85131243068&partnerID=8YFLogxK
U2 - 10.1016/j.jeurceramsoc.2022.05.066
DO - 10.1016/j.jeurceramsoc.2022.05.066
M3 - Article
AN - SCOPUS:85131243068
SN - 0955-2219
VL - 42
SP - 5303
EP - 5313
JO - Journal of the European Ceramic Society
JF - Journal of the European Ceramic Society
IS - 13
ER -