Crystal structural, thermal and mechanical properties of Yb_2+xTi_2−xO_7−x/2 solid solutions annealed at 1673 K were investigated for x from 0.05 to 1.02. From Rietveld refinements and electron density distributions determined by the maximum-entropy method for X-ray powder diffraction data, crystal structures for x ≲ 0.53 and 0.63 ≲ x ≲ 0.8 were identified as Yb₂Ti₂O₇-based pyrochlore and Yb₂TiO₅-based defect fluorite structures, respectively, while defect fluorite and Yb₂O₃-based bixbyite structures were found to coexist at x ≈ 1.02. Anisotropic distributions of the electron densities on cation sites became more noticeable for compositions near the phase boundary. Adopted model of pyrochlore structure was validated through the evaluation of defect formation energies and the comparison with theoretical values by first-principles calculations. Thermal expansion coefficients, thermal conductivities, and Young's moduli of sintered samples with x ≈ 0.05, 0.53, 0.63 and 0.69 depended strongly on x, which is ascribed to changes in structural features such as densities and oxygen-vacancy concentrations.

研究了在1673 K退火的Yb _{2+ x} Ti _{2− x} O _{7− x / 2}固溶体的晶体结构，热学和机械性能，其x从0.05到1.02。从Rietveld精修和电子密度分布确定通过X-射线粉末衍射数据，晶体结构的最大熵方法对X  ≲0.53和0.63≲ X  ≲0.8被确定为镱₂的Ti ₂ ö ₇系烧绿石和Yb ₂的TiO分别为₅基缺陷萤石结构，缺陷萤石和Yb ₂ O_3层发现系的方铁锰矿结构在共存X  ≈1.02。对于相边界附近的组成，阳离子位置上电子密度的各向异性分布变得更加明显。通过评价缺陷形成能并通过第一性原理计算与理论值进行比较，验证了所采用的烧绿石结构模型。热膨胀系数，热导率，并用烧结样品的杨氏模量X  ≈0.05，0.53，0.63和0.69上强烈地依赖X，这是归因于结构特征的变化，如密度和氧空位浓度。