Achieving strength-ductility synergy in cold-sprayed SiCp/Al composites via an SiCp architectured agglomeration strategy

The widespread application of cold-sprayed SiCp/Al composite coatings is often constrained by the inherent trade-off between strength and ductility. During the fabrication of high SiCp content composite coatings, when the SiCp concentration reaches the deposition threshold, intensified inter-particle interactions lead to destabilized SiCp behavior and various defects. To address these challenges, we propose a straightforward yet effective strategy utilizing specially designed micro-sized agglomerated SiCp. The method involves agglomerating 20 μm β-SiCp precursors into 50 μm aggregates through the incorporation and subsequent pyrolysis of a cohesive silicone resin powder, exhibits a unique self-fragmentation and capture mechanism upon impact. This mechanism enables in-situ generation of a multi-scale particle distribution, significantly enhancing SiCp retention (up to 34.8 %) while minimizing porosity (as low as 1.13 %). Systematic microstructural characterization and mechanical testing reveal that the agglomerated SiCp not only mitigates sharp-edge induced damage and reduces rebound loss, but also promotes interfacial bonding and facilitates pull-out toughening. Consequently, the resulting agglomerated SiCp/Al composite coating achieves a remarkable synergy of high ultimate tensile strength and appreciable elongation.