A Review of the Mechanical and Tribological Behavior of Cold Spray Metal Matrix Composites

Cold spray is an effective solid-state process for the fabrication of metal matrix composites where metallic, ceramic, or intermetallic reinforcements are embedded in a metallic matrix. Cold-sprayed metal matrix composites (CS MMCs) enable combining favorable properties of their constituent phases. Combinations of the ductility of metals with the high strength of ceramics or with the creep resistance of intermetallics are two typical examples. Here, we review recent advances in the understanding of the mechanical and tribological behavior of CS MMCs, with particular emphasis on the physical mechanisms and predictive understanding. We start the review with deposition mechanisms, defects, and microstructural features in CS MMCs. We continue the discussion with the mechanical behavior of CS MMCs, including elastic modulus, hardness, strength, ductility, as well as adhesive and cohesive failures. We also explore various aspects of the tribology of CS MMCs, from frictional response to abrasive and erosive wear. We discuss the effect of cold spray parameters and post-spray thermal and mechanical treatments on the microstructure and properties of CS MMCs. We connect experimental findings on the mechanics and tribology of CS MMCs with theoretical frameworks to the extent possible. Finally, we propose several critical unresolved issues in the field as future research directions.