Scanning near-field optical microscopy (SNOM) technique was applied to nanometer-scale residual stress mapping for directionally solidified Al2O3/monochromic ZrO2 and Al2O3/Cubic ZrO2(Y2O3) eutectics, which are ranked as candidates for high-strength materials at high temperatures. These eutectic composites were grown using the micro pulling down (mu-PD) method with a radio frequency heating system. Topographic images and fluorescence spectra of those eutectic composites were measured simultaneously for each pixel oil a sample. Its peak intensity, peak position, and peak width, which, respectively, correspond to the abundance of Al2O3, stress in the grain, and the anisotropy of that stress, were estimated for each fluorescence spectrum. The distribution of residual stress was observed on a sample surface with spatial resolution of 300 nm; the spatial resolution was constrained by the optical fiber aperture size. Tensile stress was observed in Al2O3 of Al2O3/mZrO(2) and compressive stress was observed in Al2O3 of Al2O3/cZrO(2). The stress distributions were visualized within a single Al2O3 grain. Considerable stress anisotropy was detected in the grain boundary between Al2O3 and ZrO2 for both eutectics. (c) 2008 Elsevier B.V. All rights reserved.