Effect of matrix modification on tensile mechanical behavior of Tyranno® Si-Ti-C-O fiber-reinforced SiC matrix minicomposite at room and elevated temperatures

The effect of the addition of borosilicate glass powder in the matrix on tensile mechanical behavior in an unidirectional Si-Ti-C-O fiber-reinforced SiC matrix minicomposite fabricated by the polymer infiltration pyrolysis (PIP) process has been studied. Tensile test of the minicomposite is carried out in an argon atmosphere at 298, 1273 and 1573 K. The Si-Ti-C-O/SiC shows a nearly linear tensile load-displacement curve which is similar to a dry fiber bundle independent of test temperature; conversely, the glass-powder-containing Si-Ti-C-O/SiC(g) exhibits a pronounced tensile load-displacement curve with a large nonlinear domain of deformation; however, this nonlinear domain became smaller at 1573 K. The matrix cracking load of Si-Ti-C-O/SiC(g) remained nearly constant at and below 1273 K, and it decreased at 1573 K. The tensile fracture load of the minicomposite is increased remarkably by the addition of a borosilicate glass powder in the matrix, but the increase was larger at and below 1273 K than at 1573 K. This increase of the tensile fracture load was attributed to more effective load transfer at the fiber/matrix interface for the Si-Ti-C-O/SiC(g) than for the SiTi-C-O/SiC. Degradation of the increase at 1573 K is due to the interface degradation decreasing interfacial load transfer capacity. (C) 2003 Elsevier Ltd. All rights reserved.