炭化物粒子分散によるムライトの高強度化に関する研究 : 第1報,SiCおよびTiC粒子分散の効果

概要

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Both mullite/SiC (0.27 μm and 1.20 μm) and mullite/TiC composite ceramics were prepared by hot-pressing at 1650℃ under 35 MPa for 4h. Room-temperature bending strength, Young's modulus, Vicker's hardness and fracture toughness were investigated as functions of SiC and TiC volume fractions (0-20%). Grain growth of mullite was prevented by the existence of dispersed particles (SiC, TiC) in the matrix. As a result, bending strength of both mullite/SiC and mullite/TiC composite ceramics was improved. In the case of the mullite/SiC system, bending strength increased with increasing SiC content and showed a maximum value of 604 MPa at 20 vol%, which was about 80% higher than that of monolithic mullite. On the other hand, fracture toughness of mullite/TiC ceramic composite was observed to increase from 2.65 to 3.9 MPa√<m> with the addition of 20 vol% TiC. Correspondingly, the bending strength increased from 330-410 MPa. The strengthening mechanism by thermal treatment in air was also investigated for mullite/SiC composite ceramics and it was concluded to be useful to increase bending strength. Detailed research on the microstructure showed that a Hall-Patch relationship was recognized for grain size and bending strength.
社団法人日本機械学会の論文
1994-12-25