Effect of mechanical properties on the ballistic resistance capability of Al2O3-ZrO2 functionally graded materials

Because Al2O3 exhibits high strength and hardness, it is prevalently used as a ceramic material. ZrO2 is often added to increase the toughness of such a material. Therefore, this study mixed Al2O3 and ZrO2 to formulate functionally graded materials (FGMs). four-layer and eleven-layer Al2O3-ZrO2 FGMS were produced from Al2O3 and ZrO2 mixtures by sintering at 1500 °C. Moreover, testing sheets were created by mixing various ratios of Al2O3 and ZrO2 to analyze their fracture toughness and hardness. The results revealed the 90% Al2O3-10% ZrO2 sheet to exhibit a hardness of 15.12 GPa, and the 50% Al2O3-50% ZrO2 sheet to attain a fracture toughness as high as 4.7 MPa m0.5. The impact resistance test involved analyzing various types of testing sheets, including the four-layer Al2O3-(0%, 10%, 20%, 30%) ZrO2 FGM, eleven-layer Al2O3-(0–100%) ZrO2 FGM, 100% Al2O3 composite material, 90% Al2O3-10% ZrO2 composite material, 70% Al2O3-30% ZrO2 composite material, and 50% Al2O3-50% ZrO2 composite material. The ballistic tests showed that FGMs of the same areal density (4.64 g/cm2) or thickness (11 mm) attained the highest energy absorption. The experimental results confirmed that FGMs can delay the formation and propagation of ceramic cones. Specifically, toughened alumina materials prevent the growth of radial and circumferential cracks, delay the formation of ceramic cones, decrease cones hitting against the back plane, and increase the penetrating resistant capability of the ceramic materials experiencing bullet impact, features important for applications in fields such as aerospace, aviation, automobile, the military industry, and biomedicine