材料科学
断裂韧性
抗弯强度
烧结
复合材料
粒度
晶界
微观结构
粒径
相(物质)
相对密度
晶粒生长
化学工程
工程类
有机化学
化学
作者
Yoshihiro Hirata,Naoto Suzue,Naoki Matsunaga,Soichiro Sameshima
标识
DOI:10.1016/j.jeurceramsoc.2010.02.026
摘要
Dense SiC (97.3–99.2% relative density) of 1.1–3.5 μm average grain size was prepared by the combination of colloidal processing of bimodal SiC particles with sintering additives (Al2O3 plus Y2O3, 2–4 vol%) and subsequent hot-pressing at 1900–1950 °C. The fracture toughness of SiC was sensitive to the grain boundary thickness which was controlled by grain size and amount of oxide additives. A maximum fracture toughness (6.2 MPa m1/2) was measured at 20 nm of grain boundary thickness. The mixing of 30 nm SiC (25 vol%) with 800 nm SiC (75 vol%) was effective to reduce the flaw size of fracture origin, in addition to a high fracture toughness, leading to the increase of flexural strength. However, the processing of a mixture of 30 nm SiC (25 vol%)–330 nm SiC (75 vol%) provided too small grains (1.1 μm average grain size), resultant thin grain boundaries (12 nm), decreased fracture toughness, and relatively large defect of fracture origin, resulting in the decreased strength.
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