Analysis of machining damage in engineering ceramics by fracture mechanics, fractography and x-ray diffraction
- Fraunhofer-Institut fuer Werkstoffmechanik, Freiburg (Germany); and others
The cost for final machining covers a significant percentage of the whole cost of a ceramic component. This is due to the difficult machining of the high performance ceramics. The high values of hardness and wear resistance, which are desired in many applications, hinder the process of machining. Only a few machining procedures are applicable to engineering ceramics e.g. grinding, polishing or ultrasonic lapping, and the rate of material removal is considerably lower than for metals. In addition crack generation in the surface regions during machining is easily possible due to the brittleness of the ceramics. The material removal during grinding, which is the most important machining procedure of engineering ceramics, takes place mainly by brittle fracture processes but also by ductile material removal. The complex stress conditions in the work piece below or in the vicinity of the grinding grits lead to a variability of cracks and crack systems like median cracks, lateral cracks or radial cracks, which extend in general {le} 50 {mu}m and which lead to the strength anisotropy of ground ceramics, if certain grinding parameters are used e.g..
- OSTI ID:
- 535633
- Report Number(s):
- CONF-950739--
- Country of Publication:
- United States
- Language:
- English
Similar Records
Surface and subsurface cracks characteristics of single crystal SiC wafer in surface machining
Working with sapphire and ruby