In‐situ fabrication of high‐strength SiC joints utilizing a novel CoCrFeNiTiMo high‐entropy alloy filler

This study utilized an innovative unalloyed CoCrFeNiTiMo hybrid powder as a joining filler to fabricate high‐strength SiC/HEA/SiC joints via in‐situ reaction. The investigation systematically examines the effects of joining parameters on microstructural evolution and mechanical properties. The filler exhibits high reactivity with SiC, addressing carbon enrichment and low‐strength issues. The resulting joining layer comprises HEA‐rich Si, Mo1.5Cr1.5Si, MoTiC2, and TiC phases. Increasing the temperature facilitates carbon diffusion, transforming TiC into MoTiC2 and forming a MoTiC2‐wrapped TiC structure. At 1400°C for 60 min, the joints attain peak flexural and shear strengths of 312 ± 16 and 137 ± 10 MPa, respectively. Additionally, the joints demonstrate excellent oxidation resistance, with a residual strength of 270 ± 7 MPa after 20 h at 900°C, and favorable high‐temperature mechanical strength, retaining 155 ± 14 MPa at 1000°C. A detailed analysis of the joint formation mechanism is conducted based on experimental results and first‐principles calculations.