Temperature effect on mechanical and thermal properties of multicomponent rare-earth zirconate pyrochlores

In order to explore the temperature-dependent structural and mechanical/thermal property evolution of pyrochlores, multicomponent rare-earth zirconates (4RE(1/4))(2)Zr2O7 (RE = La, Nd, Sm, Eu, and Gd) and corresponding single-component compounds are investigated by molecular dynamics simulations. The structural parameters and mechanical/thermal properties reported in experiments are well reproduced. With temperature enhancement, the bond lengths become large and polyhedrons tend to deform more, whereas the second-order elastic constants and polycrystalline mechanical moduli gradually reduce. It can be explained by the obvious change of (ZrO6) polyhedrons originating from the Zr-O bond stretching. Furthermore, thermal conductivities show decreasing tendency owing to a sharp decline of the phonon mean free path related to enhanced phonon scattering. As a big influence of temperature on (ZrO6) polyhedrons occurs, the multicomponent design at the Zr-site is suggested to be paid more attention. This work is expected to shield light on the design for multicomponent pyrochlores as thermal barrier coatings.