This dataset is related to the publication: "Statistical evaluation of the mechanical properties of partially oxygenated YBCO, oxygenated YBCO and oxygenated YBCO(Ag) single grains" The dataset contains the following data: "Figure_4.zip"(containing EDX maps in ".tif" or ".png" format), "Figure_5.zip" (containing optical tracking microscope images in ".tif" format), "Raw_data.xlsx" and "calculation_weibull_modulus.xlsx" The data can be opened in Microsoft Excel (.xlsx) and in image viewers (.tif and .png) The .zip folder "Figure_4" contains EDX maps showing the distribution of silver on nine positions in a YBCO(Ag) bulk sample cross-section (site 1-9). The nine files indicated with "b_w" contain thresholded images of sites 1-9 using ImageJ. The images were thresholded by converting the Ag distribution maps to 8-bit. Subsequently, the images were thresholded using the default thresholding method of ImageJ. The .zip folder "Figure_5" contains the optical tracking microscope images of cross-sections of partially oxygenated YBCO, oxygenated YBCO and YBCO(Ag) bulk superconductors. The images indicated with "thresholded" were thresholded starting with the original images. The images were cropped using the "polygon selections" and the "crop" tool. The part outside the range selected with the "polygon selections" tool were erased with the "clear outside" tool. The image was converted to an 8-bit image and thresholded using the "Sauvola" method (J. Sauvola, M. Pietikäinen, Adaptive document image binarisation, Pattern Recognit. 33 (2000) 225-236. https://doi.org/10.1016/S0031-3203(99)00055-2.), which is implemented in ImageJ under Image>Adjust>AutoLocalThreshold. The file "Raw_data.xlsx" contains the raw data used to create the plots shown in figures 4, 5 and 7. Figure 4: Area [µm^2]: Gives the area of every silver particle found in the 9 EDX maps of the investigated YBCO(Ag) bulk material. The particle sizes can be calculated from d = 2*SQRT(Area/pi) Figure 5: Shows the area of defects [%] determined form tracking microscope images of cross-sections of partially oxygenated YBCO, oxygenated YBCO and YBCO(Ag) bulk materials. Figure 7: The bulk materials were compressed in an Instron 5584 and the distance between two marking tapes was measured using a laser to determine failure load and displacement. The tensile strength was calculated from the failure load using Equation 2 (D = 15.5 mm and t = 6 mm). “calculation_weibull_modulus.xlsx”: For the determination of the Weibull modulus the tensile strength of the partially oxygenated YBCO, oxygenated YBCO and YBCO(Ag) bulk materials were ranked starting with 1 for the lowest tensile strength. F was calculated using F = (rank-0.5)/(number of samples). Subsequently, ln(tensile strength) vs ln(ln(1/(1-F))) was plotted. A linear function was fitted to the resulting data points. The slope of the fitted function is the Weibull modulus.