The Effect of Fiber Volume Fraction in Hipercomp® SiC-SiC Composites
Date
2010-09
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
New York State College of Ceramics at Alfred University. Kazuo Inamori School of Engineering.
Abstract
The role of fiber volume fraction on the mechanical properties of HiPerComp®
melt-infiltrated SiC-SiC pre-impregnated (prepreg) Ceramic Matrix Composite, CMC,
was explored. The reinforcing fiber was Hi Nicalon Type S manufactured by Nippon
Carbon Co., Japan. Room-temperature in-plane and interlaminar properties of
unidirectional and multi-directional laminates were evaluated as a function of fiber
volume fraction and microstructure. The proportional limit of the unidirectional material
increased with fiber loading in agreement with the Aveston-Cooper-Kelly, ACK, model.
The tensile properties were used to ascertain the elastic properties of the 0 and 90 plies.
The ply-level properties were used with composite beam theory to successfully predict
the flexure properties of cross-ply composites. Ply-level behavior was demonstrated
through four-point bend tests and careful selection of the stacking sequence. Flexural
proportional limits of 430 MPa were achieved in cross-ply laminates with a 2:1 bias,
matching the matrix cracking strength of the unidirectional 0 degree composites. Fiber
volume fraction was also found to have a significant effect on the creep behavior of the
CMC. An increase in fiber loading resulted in a decrease in creep rate and an increase in
rupture life and rupture strain at 1315°C. Creep-induced matrix cavitation was observed,
and the overall creep behavior was consistent with the assumption that the fiber is more
creep resistant than the matrix.
Description
Advisory committee members: William Carlson, William Carty, Olivia Graeve. Dissertation completed in partial fulfillment of the requirements for the degree of Doctorate of Philosophy in Ceramics at the Kazuo Inamori School of Engineering, New York State College of Ceramics at Alfred University
Type
Thesis