Abstract
Acoustic emission signals of sintered mullite were measured in 4-point bending tests. The specimens were prepared from a high-purity mullite powder and sintered at 1650°C for 2h. The 2ch AE signals were detected by the piezoelectric sensors on the both end surfaces of 4-point bending specimens (3mm×4mm×38mm). Detected waves were recorded in a digital wave memory, and then analyzed with a computer to obtain AE location and cumulative AE counts data. In addition, the SEM fractography and the fracture mechanics evaluation were carried out to determine the fracture origins. The experiments revealed the relation between type of fracture origins and AE signals, and new fracture models were proposed to explain the experimental results.
