1：Experimental Design and Method Selection:

High-frequency cyclic impact tests and static load indentation tests were performed using a self-developed high-frequency cyclic impact fatigue tester. The tests aimed to analyze force signals and fracture morphology under different loading conditions.

2：Sample Selection and Data Sources:

Four sapphire specimens (A-plane, C-plane, M-plane, R-plane) with dimensions 10 mm × 10 mm × 0.43 mm were used, provided by Helios New Materials Limited. Specimens were polished to average surface roughness Ra < 0.30 nm to eliminate defects and residual stress.

3：43 mm were used, provided by Helios New Materials Limited. Specimens were polished to average surface roughness Ra < 30 nm to eliminate defects and residual stress. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment includes a high-frequency cyclic impact test device with a Rockwell indenter (diameter 0.1 mm), piezoelectric force sensor (Kistler type 9203), charge amplifier (Kistler Type 5018A), data acquisition card (DEWESoft SIRIUS MINI solution), laser displacement sensor (LK-G5000 series, Keyence), scanning electron microscopy (SEM-Phenom ProX desktop and ZEISS EVO18), and white-light interferometer (Zygo NV7300). Materials include sapphire specimens and diamond indenter.

4：1 mm), piezoelectric force sensor (Kistler type 9203), charge amplifier (Kistler Type 5018A), data acquisition card (DEWESoft SIRIUS MINI solution), laser displacement sensor (LK-G5000 series, Keyence), scanning electron microscopy (SEM-Phenom ProX desktop and ZEISS EVO18), and white-light interferometer (Zygo NV7300). Materials include sapphire specimens and diamond indenter. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: For impact tests, specimens were fixed on an ultrasonic actuator, oscillated at 20 kHz with amplitudes of 4, 6, 8, 10 μm and impact times of 1, 2, 3, 4 s. Force signals were recorded. For static load tests, sequential loading-unloading was performed with feed intervals of 1 μm, maximum depths of 4, 6, 8, 10, 12, 14 μm, and holding time of 10 s. Surface morphology was analyzed using SEM and white-light interferometer.

5：Data Analysis Methods:

Force signals were analyzed for peak forces and fatigue stages. Fracture morphology was examined to identify crack systems and propose models based on crystal orientation. Three-dimensional morphology was measured for deformation analysis.