Relationship between particle interface structure and performance of cold sprayed CuCrZr deposit

Abstract

Cold spraying is considered as a promising technique for fabricating CuCrZr deposits attributed to its distinct plastic deformation feature. In the present study, the feasibility of this technique is validated through exploring correlations between the interface microstructure with mechanical and thermal properties. Assessment of structure–property correlations was attempted based on particle interface characteristics, together with Cr and Zr precipitates, and mechanical and thermal properties using electron backscatter diffraction, nanoindentation, adhesive shear strength and thermal conduction tests. Results show that annealing heat treatment reconstructs the particle interface through recovery and growth of ultrafine grains, leading to the reduction of porosity and enhancement of shear strength and toughness. Coupled with the re-crystallized fine grains and precipitation strengthening of the Cr oxide and Cu_xZr_y phase, the decrease in hardness due to the release of work hardening in the annealed deposits could be compensated, thereby demonstrating good thermal stability. Finally, the combination of decreased porosity and strengthened interface bonding causes the increased heat conductivity of the annealed deposits. Therefore, the combined technique of cold spraying and annealing heat treatment may be a potential solution for balancing the strength and thermal conductivity of CuCrZr.