Mechanism of toughening and strengthening of
Si3N4/SiC/ZrO2nanocomposites①
Si3N4/SiC/ZrO2nanocomposites①
(1.School of Physics Science and Technology, Central South University, Changsha 410083, China;
2. Department of Materials Science and Engineering, Nanchang Institute of Aeronautical Technology,Nanchang 330034, China)
2. Department of Materials Science and Engineering, Nanchang Institute of Aeronautical Technology,Nanchang 330034, China)
Abstract: The Si3N4-based nanocomposites reinforced with micro ZrO2and nano SiC particles were prepared by polarity dispersant and vacuum-sintering technology. The mechanical properties and microstructures were tested. The results show that appropriate amount of micro ZrO2and nano SiC particles, not only enhance the microhardness, but also block the excessively growth ofβ- Si3N4 and β-Si3N4grains, so they finally all grow up to uniformly pole-shaped grains. This process is similar to the strengthening and toughening mechanism of grain whiskers and makes a remarkable improvement on the toughness. Compared with Si3N4 ceramic, the toughness of Si3N4 /SiC /ZrO2 nanocomposites are increased from 6.2 MPa ·m1/2to 11 MPa·m1/2.
Key words: Si3N4; nanocomposites; toughening; strengthening