Effects of Cu content on the wettability of SiC with Al-Ti-Si-xCu alloy and bending strength of resulting SiC matrix composite

Abstract The effects of the addition of Cu in an Al-Ti-Si alloy on the wettability of the ceramic SiC with respect to the resulting Al-Ti-Si-xCu alloy as well as the bending strength of the resulting composite were investigated. The melting point of the Al-Ti-Si-xCu alloy decreased with an increase in the Cu content, which facilitated the diffusion of the alloying elements. The first and second stages of the wetting process were promoted. The contact angles of 0Cu, 5Cu, and 10Cu after heating at 900 °C for 10 min were 102°, 90° and 89°, respectively. However, after 210 min, they were similar at approximately 40°, as no new phases were formed at the interface. In addition, the three-point bending strength of the infiltrated SiC ceramic samples was almost twice that of the original one. As the Cu content was increased from 0 to 10 wt%, the relative volume fraction of Ti3Si(Al)C2 increased. However, for a Cu content of 10 wt%, the bonding rate between Al and SiC decreased. Therefore, the three-point bending strength of the infiltrated composite was the highest at 433 MPa in the case of the sample infiltrated with the 5Cu alloy at 900 °C for 6 h.