Uniform TitleHigh temperature/high strength discrete fiber reinforced composites
NameDeFazio, Christian F. (author), Balaguru, Perumal (chair), Maher, Ali (internal member), Najm, Husamuddin (internal member), Rutgers University, Graduate School-New Brunswick,
SubjectCivil and Environmental Engineering,
Heat resistant materials,
Heat resistant alloys,
Materials at high temperatures,
DescriptionMost of the high temperature resistant composites are made using ceramic
matrices. Typically these composites are processed at temperatures higher than the
operating temperatures. The results presented in this thesis focus on the development of
an inorganic matrix composite that can be processed at temperatures ranging from 80 to
400° C and can withstand temperatures up to 1500° C. The composites can be fabricated
using inexpensive mold-cast techniques or vacuum bagging techniques. Short discrete
fibers can be incorporated in the matrix to improve mechanical properties.
The composite is a two component system consisting of: potassium/sodium
silicate solution and a powder component containing; silica, alumina, fillers, fibers, flow
enhancing additives and activators. The major parameters evaluated in this dissertation
are: (i) influence of fiber type and fiber content, (ii) matrix composition in terms of
silica/alumina ratio, (iii) fabrication techniques, (iv) influence of curing temperature and
(v) influence of exposure to temperatures varying from 200 to 1500° C. The response variables were: the integrity of the samples after high temperature exposure and the mechanical property of the composite. The fiber types consisted of: economical bulk alumina fibers, alumina fibers in paper form and uniform-short alumina fibers. The fiber content varied from 4 to 13 percent by weight of total matrix. Silica to alumina ratios were varied from 1 to 5. Fabrication techniques investigated include: compression molding using wetted alumina fiber papers and simple casting using a mold and vacuum bagging technique.
The major findings are as follows:
• Both mold-casting and vacuum bagging techniques can be effectively used for
•Optimum curing temperature is 400° C
•For composites with bulk-economical alumina fibers the maximum flexural strength is 65 Mpa and the maximum flexural modulus is 52 GPa
•These values can be increased to 130 MPa and 85 GPa by using high quality fibers
•The densities for composites with short fibers range from 2000 to 2800 kg/m3
•Typically higher density leads to higher strengths
Note[bibliography] Includes bibliographical references (p. 74-76).
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.