Integrated computational investigation of interfacial bonding and stress mitigation mechanisms in C/C-SiC/410B stainless steel brazed joints

The reliable joining of ceramic matrix composites (CMCs) with metals is critical for applications in extreme environments, particularly in aerospace thermal protection systems and advanced energy equipment. However, achieving robust joining remains a significant challenge, primarily due to the detrimental effects of complex interfacial reactions and residual stress accumulation arising from significant thermal-physical mismatches. In this study, sound joining of C/C-SiC composites to 410B stainless steel was achieved using a CuMn filler, forming a gradient interface consisting of (Fe, Cr, Si), (Cu, Mn), and (Fe, Cr)₇C₃/(Fe, Cr)₃Si layers. To clarify the strengthening mechanisms, an integrated computational framework was established to link intrinsic bonding characteristics with macroscopic performance. At the atomic scale, first-principles calculations indicated that substantial d-p orbital hybridization in new phases increased the interfacial work of adhesion by 49.1%, which in turn strengthened chemical bonding. Transitioning to the mesoscopic scale, thermodynamic and kinetic analyses identified that a significant chemical potential gradient (Δμ_Cr‐Si = 152.7 kJ/mol) acted as the primary driving force for the diffusion-controlled growth of the reaction layer. At the macroscopic scale, finite element simulations indicated a U-shaped trend in residual stress. Optimizing the reaction layer thickness at 980 °C mitigated thermal mismatch and reduced the peak stress to 596.24 MPa. As a result, the maximum shear strength reached 21 MPa. This study not only elucidates the specific bonding mechanism of C/C-SiC/410B SS joints but also offers a theoretical integrated strategy for designing heterogeneous interfaces between CMCs and metals.