Improved mechanical strength of the C/C–Mo joints by introducing MoNiSi ternary compounds as the main phase of the interlayer

In order to improve the mechanical performance of the C/C–Mo joint, MoNiSi ternary compounds were designed as the main phase of the interlayer. Utilizing NiCrSi–Ti as the braze filler, these compounds were formed and uniformly distributed in the C/C–Mo joint at 1330 °C without any pressure. As MoNiSi was introduced to the joint, its shear strength is up to 46.10 MPa, which is 29% higher than the joint without MoNiSi brazed with NiCr–Ti filler. MoNiSi ternary compounds restrain the formation of the brittle binary silicides, and the uniform interlayer with MoNiSi and Ni-based solid solution reduces the residual thermal stress in the joint via plastic deformation, avoiding the formation of defects. Furthermore, the existence of residual Si is beneficial to the formation of a Ni-based reaction layer at the C/C side, resulting in a strong bonding between C/C composites and braze. The MoNiSi with a high hardness would result in the deflection of crack, consuming more energy, which plays a positive role in the bonding performance of the C/C–Mo joint.