Cook Robert F, Michaels Chris A
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
J Res Natl Inst Stand Technol. 2019 Aug 27;124:1-15. doi: 10.6028/jres.124.020. eCollection 2019.
Stress measurements in single-crystal and polycrystalline alumina are revisited using a recently developed optical fluorescence energy shift method. The method simultaneously utilizes the R and R Cr-related ruby line shifts in alumina to determine two components of the stress tensor in crystallographic coordinates, independent of the intended or assumed stress state. Measurements from a range of experimental conditions, including high-pressure, shock, quasi-static, and bulk polycrystals containing thermal expansion anisotropy effects, are analyzed. In many cases, the new analysis suggests stress states and stress magnitudes significantly different from those inferred previously, particularly for shock experiments. An implication is that atomistic models relating stress state to fluorescence shift require significant refinement for use in materials-based residual stress distribution analyses. Conversely, the earliest measurements of fluorescence in polycrystalline alumina are shown to be consistent with recent detailed measurements of stress equilibrium and dispersion.
利用最近开发的光学荧光能量转移方法，重新研究了单晶和多晶氧化铝中的应力测量。该方法同时利用氧化铝中与R和R Cr相关的红宝石线位移来确定晶体学坐标中应力张量的两个分量，而与预期或假设的应力状态无关。分析了一系列实验条件下的测量结果，包括高压、冲击、准静态以及含有热膨胀各向异性效应的块状多晶。在许多情况下，新的分析表明应力状态和应力大小与先前推断的有显著差异，特别是对于冲击实验。这意味着将应力状态与荧光位移相关联的原子模型在用于基于材料的残余应力分布分析时需要进行重大改进。相反，多晶氧化铝中最早的荧光测量结果被证明与最近对应力平衡和色散的详细测量结果一致。
