Publica
Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten. Strength and fracture toughness of the ESIS silicon nitride reference material
Festigkeit und Bruchzähigkeit eines ESIS Siliziumnitrid Referenzmaterials
| Fracture Mechanics Beyond 2000 : Proceedings of the 14th Bienniel Conference on Fracture - ECF 14 - held in Cracow, Poland 8-13 September, 2002
West Midlands: EMAS Publications, 2002
ISBN: 83-88906-04-6 |
| European Conference on Fracture (ECF) <14, 2002, Cracow> |
|
| Englisch |
| Konferenzbeitrag |
| Fraunhofer IKTS () |
| round robin testing; silicon nitride; strength; fracture toughness; elevated temperature |
Abstract
The ESIS Technical Committee for Ceramics (TC6) is running a joint program to characterise a commercial silicon nitride ceramic with respect to all properties necessary to a proper design process. In this paper some preliminarily results of measurements on the ESIS Reference Silicon Nitride are presented: the room temperature 4-pt. bending strength is around 870 MPa and the 3-pt. bending strength is around 990 MPa. These two data clearly demonstrate the volume dependence of strength, which can consistently be described with the Weibull theory and a Weibull modulus of about 15. The room temperature fracture toughness of the material is 4,9 MPam1/2 (determined with the SENB V method). IF-toughness values are between 4,8 to 7,9 MPam1/2. Although some sub-critical crack growth exists at room temperature (the crack growth exponent is around 50), severe time dependent damage starts around 1000°C.