505 セラミックスの強度変動におよぼす内部粗大欠陥分布の影響(セラミック/セラミック基複合材料2)

概要

論文の詳細を見る
Macro-defects were examined in detail with a new optical microscopy, and their relevance to the strength and its distribution was discussed for alumina ceramics. The ceramics was prepared with the commercial alumina granules of very fine powder by pressing method followed by sintering. In the new microscopy, thin slices were prepared from the ceramics and examined with an optical microscope in the transmission mode. Macro-defects were noted as dark features or shadows in this examination. The relation between the size and population of macro-defects was established by analyzing photomicrographs. The strength of alumina was successfully simulated based on the fracture mechanics with the defect size distribution. In the simulation, defects with the determined size distribution were placed randomly in the specimen. Critical fracture stresses were calculated for large candidate defect under 4-point loading and the smallest of them governs the strength of the particular specimen. The calculated strength and Weibull modulus agreed very well with experimental results. And, relationship between defect size distribution and strength was demonstrated by the calculation for various defect size distributions.
社団法人日本機械学会の論文
2007-11-16