Features of crystal structures and thermo‐mechanical properties of weberites RE <sub>3</sub> NbO <sub>7</sub> (RE=La, Nd, Sm, Eu, Gd) ceramics
Lin Chen, Guo Jun, Yuke Zhu, Mingyu Hu, Jing Feng
Abstract
Abstract The features of crystal structures, thermo‐mechanical properties and their dominant mechanisms of weberites RE 3 NbO 7 were studied as high‐temperature oxides. We concentrated on connections between structures and thermo‐mechanical properties, the influences of bond lengths, lattice distortion degrees and microstructures on these properties were estimated. The shortening of bond length and increment of bonding strength would lead to the increase of mechanical properties. The Vickers hardness (4.5‐7.8 GPa) and toughness (0.5‐1.6 MPa·m 1/2 ) of weberites RE 3 NbO 7 are enhanced by grain refinement and increment of bond strength, while crystal structures, bond lengths, and lattice distortion degrees influenced their Young's modulus (100‐170 GPa). Nano‐indentation was applied to test the influence of microstructures on modulus and hardness. The dominant mechanisms for mechanical properties and thermal conductivity were proposed, which was conducive to properties tailoring and engineering applications of weberites RE 3 NbO 7 oxides.