Design and diffusion kinetics of cold-sprayed multilayer interlayers for low-temperature, short-time joining of SiC/GH3536

Abstract

To achieve reliable joining between SiC ceramics and a nickel-based superalloy and thereby fully exploit the respective performance advantages of both materials, a Ti/Cu/Ni/Cu/Ti multilayer interlayer was fabricated by cold spray and used for joining SiC to GH3536 alloy. The effects of joining temperature and holding time on the microstructure and mechanical properties of the joints were systematically investigated, and the joint formation mechanism was analyzed. The results indicate that a diffusion-couple structure formed within the cold-sprayed interlayer during the joining process. Compared with conventional binary diffusion-couple models based on the Darken equation and the Arrhenius equation, this structure significantly enhances interdiffusion of elements, thereby reducing the required joining temperature and holding time. Reliable joining was achieved at 900 °C with a holding time of 5 min, while a maximum shear strength of 63.94 MPa was obtained at 920 °C for 5 min. Further analysis reveals that the Cu-Ti liquid phase formed during joining promotes wetting and bonding, whereas the Ni layer acts as a stress-buffer layer, effectively alleviating residual stresses in the joint region. This study provides a new and efficient approach for joining SiC ceramics and their composites with nickel-based alloys, and offers new insights into the joining of ceramic–metal dissimilar materials.