Browsing by Author "Ondracek, Gerhard"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- ItemBorosilicate glass matrix composites reinforced with short metal fibres(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1994) Boccaccini, Aldo R.; Ondracek, Gerhard; Syhre, ClaudiaThe reinforcement of a borosihcate glass with Hastelloy X short fibres is discussed. A fabrication process consisting of wet mixing of the glass powder and the metallic fibres and hot pressing of the mixtures was developed. Composites containing 15 vol.% fibres homogeneously distributed in a near fully dense glass matrix were obtained. Both Young's modulus and fracture strength increased with increasing volume fraction of fibres. The experimental values for the Young's modulus are in agreement with theoretical predictions. No fibre pull-out during fracture was detected and there is a good interfacial bond. By means of a rule-of-mixture calculation for the fracture energy, a five-fold increase in fracture toughness for composites containing 15 vol.% fibres can be predicted.
- ItemViscous sintering of non-spherical borosilicate-glass powder(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1992) Boccaccini, Aldo R.; Ondracek, GerhardDensification by viscous flow - instead of diffusion - may be investigated by comparing densification rates and flow rates without the effect of external load, if possible. This is why the sintering of a borosilicate-glass powder was investigated using a hot-stage microscope. The samples sintered at 888 Κ showed shrinkage anisotropy, being the ratio of the axial to the radial shrinkage < 1. The flow rate varies linearly with the densification rate due to anisotropic densification; and the ratio between flow rate and densification rate may be altered by modifying the grade of anisotropy in densification. Scherer's theory has been used to compare experimental and theoretical values and the interdependence between densification rate and density. Deviations are discussed.