High temperature bending behavior of polycrystalline Si and SiC particle-reinforced Si matrix composites

Abstract

Abstract Silicon (Si) has been widely applied in silicon carbide (SiC) composites for high temperature components. In this study, high temperature bending behavior of polycrystalline Si and silicon carbide particle-reinforced Si matrix composites (SiC/Si) was evaluated. Polycrystalline Si showed large deformation above 1220°C due to ductile transition and multiple cracking. The transition temperature of polycrystalline Si was about 500°C higher than single crystal Si because grain boundary of Si disturbed dislocation motion. On the other hand, the SiC/Si composites showed less ductility than Si because of significant brittleness of SiC even at high temperature. In the case of SiC/62vol%Si composite, it flowed at only 1350°C by debonding at the interface between SiC and Si. High temperature maximum strength of this composite was kept around 400 MPa.