2536 Increase of structural integrity of machined Al_2O_3/SiC composite ceramics using Crack-healing
Details
Alumina is used in various fields as a machined component. However it has a weakness in low fracture toughness. Thus, countless cracks may be initiated randomly by machining, and the cracks decrease the component's mechanical properties and reliability. To overcome this problem, crack-healing ability could be a very useful technology. In this study, Al_2O_3/SiC particle composite was sintered. This alumina exhibits excellent crack-healing ability. Small specimens for bending were made from the Al_2O_3/SiC. A semicircular groove was machined hardly using diamond ball-drill. The local fracture stress was reduced from approximately 820MPa to 300MPa by machining. The machined specimens were crack-healed under various conditions. The fracture stress of these specimens after crack-healing was evaluated systematically at R.T. It was found that the local fracture stress of the machined specimen recovered almost completely by crack-healing. Therefore, it was concluded that crack-healing could be an effective method for improving the structural integrity of machined alumina while reducing machining costs.
