The supplementary materials for the study "Achieving room temperature plasticity in brittle ceramics through elevated temperature preloading" include figures, tables, and movies that support the main findings. Figures S1 to S8 and Table S1 provide detailed microstructural analysis and mechanical behavior of titanium dioxide (TiO₂) and aluminum oxide (Al₂O₃) micropillars under various deformation conditions. Figure S1 shows defect formation in TiO₂ (DT1 specimen) after deformation to 3% strain, revealing strain contours, subgrains, and dislocations. Figure S2 presents similar observations for TiO₂ (DT3 specimen) deformed to 11% strain, showing cracks, stacking faults, and grain boundary changes. Figure S3 illustrates defects in Al₂O₃ (DA1 sample) after RT deformation, including cracks and dislocations. Figures S4 to S6 show microstructural changes in Al₂O₃ (DA3 specimen) after elevated temperature preloading and deformation. Figure S7 provides TEM images under different beam conditions, showing dislocation structures and SAED patterns. Table S1 summarizes the Burgers vectors of dislocations based on visibility criteria. Figure S8 presents uniaxial microcompression tests on SPS polycrystalline TiO₂ at different temperatures, showing brittle failure at ~2% strain and enhanced plasticity after preloading. The movies (S1 to S9) provide in situ SEM videos of micropillar compression under various conditions, capturing deformation processes and crack propagation. These materials collectively support the study's conclusion that elevated temperature preloading can induce room temperature plasticity in brittle ceramics by promoting dislocation activity and microstructural changes.The supplementary materials for the study "Achieving room temperature plasticity in brittle ceramics through elevated temperature preloading" include figures, tables, and movies that support the main findings. Figures S1 to S8 and Table S1 provide detailed microstructural analysis and mechanical behavior of titanium dioxide (TiO₂) and aluminum oxide (Al₂O₃) micropillars under various deformation conditions. Figure S1 shows defect formation in TiO₂ (DT1 specimen) after deformation to 3% strain, revealing strain contours, subgrains, and dislocations. Figure S2 presents similar observations for TiO₂ (DT3 specimen) deformed to 11% strain, showing cracks, stacking faults, and grain boundary changes. Figure S3 illustrates defects in Al₂O₃ (DA1 sample) after RT deformation, including cracks and dislocations. Figures S4 to S6 show microstructural changes in Al₂O₃ (DA3 specimen) after elevated temperature preloading and deformation. Figure S7 provides TEM images under different beam conditions, showing dislocation structures and SAED patterns. Table S1 summarizes the Burgers vectors of dislocations based on visibility criteria. Figure S8 presents uniaxial microcompression tests on SPS polycrystalline TiO₂ at different temperatures, showing brittle failure at ~2% strain and enhanced plasticity after preloading. The movies (S1 to S9) provide in situ SEM videos of micropillar compression under various conditions, capturing deformation processes and crack propagation. These materials collectively support the study's conclusion that elevated temperature preloading can induce room temperature plasticity in brittle ceramics by promoting dislocation activity and microstructural changes.