Achieving simultaneously improved tensile strength and ductility of a nano-TiB2/AlSi10Mg composite produced by cold spray additive manufacturing

The premature failure of components due to poor inter-particle bonding is the most critical issue in cold spray (CS) additive manufacturing. Herein, a hybrid strategy combining gas-atomization (involving in-situ reaction), CS, and post-friction stir processing was proposed to design a nano-TiB2/AlSi10Mg composite. Multiscale characterization in terms of X-ray diffraction and scanning and transmission electron microscopy was conducted to track microstructure evolution for better understanding the mechanisms determining mechanical performance of the produced composites. The results showed simultaneous improvement in both ultimate tensile strength (365 +/- 35 MPa) and ductility (16.0 +/- 1.2%), which represents a breakthrough. The strengthening and toughing mechanisms were attributed to the fine matrix grains with the significantly improved metallurgical inter-particle bonding, and the uniformly distributed TiB2 nanoparticles as reinforcement that was strongly bonded with the matrix (i.e. the formation of semi-coherent TiB2/Al interface). This study provides new guidance for hybrid additive manufacturing of metal matrix composites with high performance.