Characterizing Property of States: Effect of Defects on the Coefficient of Thermal Expansion and the Specific Heat Capacity of ZrB<sub>2</sub>

• 作者: Jude O. Ighere P. Alex Greaney
• 来源期刊: 玻璃与陶瓷期刊(英文)
• 学科: 工学
• 关键词: ZIRCONIUM DIBORIDE ZrB2 Thermal Expansion DEFECTS Molecular Dynamics Specific Heat Capacity
• 年，卷（期）: 2020,（2）
• 页码范围: 15-27
• 页数: 13页
• 分类号: TB3

摘要

Thermal storage potential and thermal expansion are characteristic properties for extreme applications. ZrB2 is a candidate for advanced applications in aircraft and fusion reactors. This article presents density functional theory calculations of its states, microstructure and quasi-harmonic levels calculations of thermophysical properties. Band structure highlighted dynamical instability with metallic impurities in ZrB2 structure based on frequency modes. The observed projected density of states (PDOS) appropriate 4d orbital of Zr dominated at low frequency both in perfect crystal in the presence or absence of covalent impurities while B 2s and 2p orbitals dominate higher frequency states. Temperature dependency and anisotropy of coefficient of thermal expansion (CTE) were evaluated with various impurities. Various thermodynamic properties like entropy and free energy were explored for degrees of freedom resulting from internal energy changes in the material. Computed results for heat capacity and CTE were compared to available numerical and experimental data.