Effect of Interface Coating on High Temperature Mechanical Properties of SiC–SiC Composite Using Domestic Hi–Nicalon Type SiC Fibers

Abstract

Here we show that when the temperature exceeded 1200 °C, the tensile strength drops sharply with change of fracture mode from fiber pull-out to fiber-break. Theoretical analysis indicates that the reduction of tensile strength and change of fracture mode is due to the variation of residual radial stress on the fiber–matrix interface coating. When the temperature exceeds the preparation temperature of the composites, the residual radial stress on the fiber–matrix interface coating changes from tensile to compressive, leading to the increase of the interface strength with increasing temperature. The fracture behavior of SiC–SiC composites changes from ductile to brittle when the strength of fiber–matrix interface coating exceeds the critical value. Theoretical analysis predicts that the high temperature tensile strength can increase with a decrease in fiber–matrix interface thickness, which is verified by experiments.

Influence of Oxidation Damages on Mechanical Properties of SiC/SiC Composite Using Domestic Hi-Nicalon Type SiC Fibers

“…Interphase usually plays a key role in determining the mechanical properties of materials [ 18 – 20 ]. In our previous work, both theory and experiment show that once the interface binding strength exceeds the critical value, the composite failure mode converts from fiber pull-out ductile failure mode to fiber break brittle failure mode and the tensile strength of SiC/SiC drops sharply [ 21 ]. It is worthy to mention that because sufficient SiO 2 filled the pores on the material surface, oxygen atoms prevent further entry into the material [ 22 , 23 ].…”

Special Issue: Mechanical Properties of Advanced Multifunctional Coatings

“…There has been considerable effort dedicated to studying how the interface affects mechanical properties of SiC-SiC composites. Through a combination of experimental measurement and theoretical analysis, Jin et al [15] investigate the tensile properties of SiC-SiC composites reinforced by domestic Hi-Nicalon type SiC fiber at high temperature and illuminate how the interface coating affext the mechanical property variations. The experimental results show that tensile strength dramatically drops above 1200 C, and fiber-pull-out fracture mode changes to fiber-break.…”