Rupture différée en fatigue statique, aux températures intermédiaires (>800°C), de fils et de fibres à base de carbure de Silicium

GAUTHIER, Wilfried

Thèses de doctorat

Date de soutenance

2006-12-22

Résumé en anglais

SiC fiber reinforced ceramic matrix composites are sensitive to delayed failure under low stresses at temperatures between 600°C - 800°C. In a previous work, this phenomenon was related to slow crack growth in Nicalon tows. Data were obtained on Nicalon tows only. The present paper investigates the static fatigue behavior of Hi- Nicalon and Hi-Nicalon S fibers. Tests were carried out on single filaments and on multifilament tows, at temperatures of 500°C and 800°C, in air. Stress-rupture time diagrams were determined for single filaments and tows at these temperatures. The determination of these diagrams is quite straightforward for tows. A specific procedure needed to be developed for the single filaments. Relationships between lifetimes of single filaments and those of tows were established. A model based on slow crack growth in fibers taking into account temperature allowed sound predictions of lifetimes that were in excellent agreement with experimental results. The model allowed the influence of various parameters including size effects to be anticipated. The strength-probability-time diagrams were established for the single filaments. These diagrams may be an aid to composite designers.< Réduire

Mots clés

Physico-Chimie de la Matière Condensée

carbure de silicium

fatigue

URI

https://oskar-bordeaux.fr/handle/20.500.12278/25483

Unités de recherche

Thèses de l'Université de Bordeaux avant 2014

Voir/Ouvrir

Métadonnées

Partager cette publication !

Licence d’utilisation du document