In this work, microstructural dependence of thermal conductivity of two polycrystalline zircaloy-4 samples was analyzed by using an extended Raman thermometry method. The thermal conductivity values in examined microstructures were found to vary spatially from 11 to 13 W m⁻¹K⁻¹. These values are in the range reported by other bulk measurements that do not consider spatial distribution. The Kapitza thermal resistance model is shown to describe the measured dependence of thermal conductivity as a function of grain size. Thermal resistance from grain boundaries and inhomogeneities are identified as two potential contributors to the thermal conductivity reduction. Nanoindentation tests were performed to obtain the local elastic modulus distribution in the analyzed samples. The thermal conductivity values increase with elastic modulus increasing in each sample. This result indicates a possibility that at room temperature phonon thermal conductivity makes a non-negligible contribution to the total thermal conductivity in zircaloy-4.

在这项工作中，通过使用扩展拉曼测温方法分析了两个多晶Zircaloy-4样品的导热系数的微观结构依赖性。发现所检查的微结构中的导热系数在空间上从11到13 W m ^-1 K ^-1变化。这些值在其他不考虑空间分布的批量测量报告的范围内。显示了Kapitza热阻模型，该模型描述了所测得的导热系数与晶粒尺寸的关系。来自晶界和不均匀性的热阻被认为是导致热导率降低的两个潜在因素。进行纳米压痕测试以获得所分析样品中的局部弹性模量分布。在每个样品中，热导率值随弹性模量的增加而增加。该结果表明在室温下声子热导率对Zircaloy-4的总热导率的贡献不可忽略的可能性。