1447 窒化ケイ素/炭化ケイ素複合材のき裂進展挙動に及ぼすき裂治癒効果のその場観察(S07-2 セラミックスおよびセラミックス系複合材料II,21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

概要

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Effects of crack-healing on crack propagation behavior in Si_3N_4/SiC were investigated by in-situ observation. The in-situ observation was conducted for two materials which were sintered with different sintering additives and subjected to raising stress at several temperatures, environment (Air, N_2) and loading rate. As a result, it was revealed that suppression of crack propagation and increase of fracture strength were occurred at high temperature in both Air and N,. These effects in N_2 were caused by release of tensile residual stress at high temperature. Moreover, these effects in Air were affected by crack-healing in addition to release of tensile residual stress. These two factors, crack-healing and release of tensile residual stress were dependent on time. So the effect of these factors on increase of fracture strength was higher, as the loading rate was smaller. From these result, it became clear that release of tensile residual stress as well as crack-healing play an important role in suppression of crack propagation and increase of fracture strength.
2008-08-02