Improved the mechanical properties of SiCf/SiC-GH536 joints by in-situ introducing better toughness MoNiSi phase to the brazing seam

Brazing, a crucial technology for connecting composites with metals, emerges as an effective solution to the intricate challenges posed by alternative joining methods. This investigation employs foam Ni and MoNi as intermediary layers to establish connections between silicon carbide reinforced silicon carbide composites (SiCf/SiC) and GH536 superalloy. The diverse joint structures, scrutinizing their intricate impact on the mechanical properties of the brazed joints are systematically explored in this study. Findings reveal distinctive characteristics depending on the intermediary layer: Ni foam widens the brazing seam, with a significant portion of Ni elements in the nickel foam adopting the Ni(s, s) form within the brazing seam. Meanwhile, MoNi foam as the intermediary layer prompts the in-situ formation of a substantial MoNiSi phase within the brazing seam. The alternation between the MoNiSi and FCC phases contributes to a harmonized internal stress state within the joint, resulting in an impressive strength of 106.7 MPa. This study delineates a novel technical trajectory for the practical engineering application of SiCf/SiC composites.