Significant increase in mechanical performance of the C/C-Mo joint by controlling the interfacial defects

Abstract

To realize the high-strength bonding of C/C composites and metal Mo, Ti was utilized to modify the BNi-5 filler by controlling the interfacial defects. As 5 wt% Ti was used to modify the filler, the doped Ti could absorb the surrounding Mo atoms and prevent them from reacting with liquid Ni-based filler to form MoNiSi compounds in the carbon-side interfacial region during the joining process, reducing the consumption of liquid filler at the interfacial area. Thus, the sufficient liquid filler offers the necessary formation conditions for a dense interfacial layer without obvious defects like pores, increasing shear strength from 19.56 to 45.80 MPa. Excess Ti would have a negative effect on the joint strength since numerous brittle TiC would be produced to form new defects in the interfacial layer, and the high-performance MoNiSi ternary compounds in the interlayer were restrained due to the formation of brittle Ni-Ti-Si compounds with a big size. This work provides an effective strategy to significantly enhance joint strength by controlling the interfacial defects.