Improvement of Mechanical Properties of Al_2O_3-SiC Composite with ZrO_2 (3Y) Particles

摘要

The mechanical properties of Al_2O_3-SiC based composites were improved by the addition of ZrO_2(3Y) particles in the range of 10 to 25 vol.%. Al_2O_3-SiC/ZrO_2(3Y) composites were manufactured by pressureless sintering at 1550, 1600, and 1650°C. Sintered composites were characterized for density, XRD, microstructure and mechanical properties such as flexural strength, fracture toughness and hardness. The results showed that the highest flexural strength of 250 MPa was obtained with 25 vol.% ZrO_2(3Y) composite sintered at 1600°C due to higher density and smaller Al_2O_3 grains in comparison with samples sintered at 1550°C and 1650°C, respectively. The maximum fracture toughness of 5.66 MPa.m172 was obtained with 20 vol.% ZrO_2(3Y) sintered at 1600°C. The highest hardness of 9.16 GPa was obtained with composite of 10 vol.% ZrO_2(3Y) sintered at 1600°C as it contains the largest amount of hard SiC.