き裂治癒と保証試験による構造用セラミックスの信頼性保証

—応力集中部材への適用と保証応力の温度依存性—

抄録

Structural ceramics are brittle and sensitive to flaws. As a result, the structural integrity of a ceramic component may be seriously affected by inherent flaws. Self-crack-healing is an excellent answer to this problem. At the moment, however, there is no technique to heal embedded flaws. Therefore, a technique to guarantee the reliability of ceramics components is demanded, and thus a technique using crack-healing followed by proof test was developed by K. Ando et al to accomplish this. With this technique, testing on the mechanical behavior of the crack-healed zone is very important for ensuring the structural integrity of ceramic component. In this study, firstly Al₂O₃/SiC composite with excellent crack-healing ability was sintered. Secondly, a semicircular groove was hardly machined using a diamond ball-drill. Third, a proof test was carried out on the crack-healed sample. Last, using the crack-healed and proof-tested sample, a fracture test was carried out at 1373 K. The measured local fracture stress (σ_LF) was compared with the theoretical minimum fracture stress guaranteed (σ_G ^T) at 1373 K. As the results, σ_G ^T showed good agreement with the σ_LF at 1373 K. Thus, the crack-healing followed by proof test was an excellent technique to guarantee the reliability of machined Al₂O₃/SiC composite.