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 degrees 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 degrees C, and favorable high-temperature mechanical strength, retaining 155 +/- 14 MPa at 1000 degrees C. A detailed analysis of the joint formation mechanism is conducted based on experimental results and first-principles calculations. Specific joining process and performance characterisation. image