Theoretical Investigation on Mechanical and Thermal Properties of a Promising Thermal Barrier Material: Yb3Al5O12

An investigation on the mechanical and thermal properties of Yb3Al5O12 is conducted by a combination of first-principles calculations and chemical bond theory calculation. Density functional theory (DFT) computations were performed for the structural, mechanical, and thermal properties, and the results are confirmed by chemical bond theory. Based on the calculated equilibrium crystal structure, heterogeneous bonding nature is revealed. The full set of elastic constants and mechanical properties of Yb3Al5O12 are presented for the first time. The thermal expansion coefficient of Yb3Al5O12 is calculated to be 7.5 × 10−6 K–1 by chemical bond theory. In addition, the minimum thermal conductivity of Yb3Al5O12 is estimated to be 1.22 W m−1 K−1, and the origin of such low thermal conductivity is discussed. Our theoretical results highlight the potential of Yb3Al5O12 as a prospective thermal barrier coating material.