Strength and crack growth data for fusion relevant ceramics
Description
Microwave heating is being considered as an external plasma heat source for fusion reactor systems. The window separating the reactor vacuum and the electron tube vacuum is heated up as a result of dielectric losses. The temperature gradients in the window cause thermal stresses. These stresses are responsible for failure and finite lifetimes of the ceramic materials. Three failure modes are of special interest: Spontaneous failure, failure after subcritical crack growth and cyclic fatigue leading to a finite lifetime. A number of ceramic materials has been investigated. The results are reported by Weibull plots (strength), v-K-curves (subcritical crack growth) and da/dN-ΔK-curves (cyclic fatigue). For a number of materials also the fracture toughness KI,c is given. (orig.)
Availability note (English)
MF available from INIS under the Report Number.Abstract (German)
Der Einsatz von Gyrotrons ist fuer Fusionsreaktoren geplant um das Plasma auf Zuendbedingungen zu bringen. Zur Trennung des zum Betrieb des Gyrotron notwendigen Hochvakuums vom Plasma werden Keramikfenster eingestzt. Aufgrund der dielektrischen Verluste heizt sich die Keramik auf und die sich einstellenden thermischen Spannungen koennen sofortiges oder zeitlich verzoegertes Versagen des Fensters bewirken. Die dabei auftretenden Versagensarten sind: Erreichen der Kurzzeitfestigkeit, Versagen nach vorausgegangenem unterkritischen Risswachstum sowie Versagen durch zyklische Ermuedung. Die Messergebnisse an einer Reihe von Keramiken werden in Form von Weibull-Diagrammen (Festigkeit), v-K-Kurven (unterkritisches Risswachstum) und da/dN-Δ-Kurven (Ermuedung) mitgeteilt. Fuer einige der betrachteten Materialien werden zusaetlich Daten der Risszaehigkeit angegeben. (orig.)
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Additional details
Publishing Information
- Imprint Pagination
- 43 p.
- ISSN
- 0303-4003
- Report number
- KFK--5409
INIS
- Country of Publication
- Germany
- Country of Input or Organization
- Germany
- INIS RN
- 26039618
- Subject category
- S70: PLASMA PHYSICS AND FUSION TECHNOLOGY; S36: MATERIALS SCIENCE;
- Descriptors DEI
- ALUMINIUM NITRIDES; ALUMINIUM OXIDES; CERAMICS; CRACK PROPAGATION; FAILURES; FATIGUE; LIFETIME; MICROWAVE HEATING; SAPPHIRE; THERMAL STRESSES; THERMONUCLEAR REACTOR MATERIALS; WINDOWS; ZIRCONIUM OXIDES
- Descriptors DEC
- ALUMINIUM COMPOUNDS; CHALCOGENIDES; CORUNDUM; HEATING; MATERIALS; MECHANICAL PROPERTIES; MINERALS; NITRIDES; NITROGEN COMPOUNDS; OPENINGS; OXIDE MINERALS; OXIDES; OXYGEN COMPOUNDS; PNICTIDES; STRESSES; TRANSITION ELEMENT COMPOUNDS; ZIRCONIUM COMPOUNDS