Submicrometer scale mapping of microstructure and mechanical properties of cold sprayed copper.

In this study, a detailed investigation is conducted on cold sprayed copper coatings in their as-deposited state as well as after annealing at 350 °C for 1 h. The local variations of microstructure and hardness are revealed through a combination of electron backscattered diffraction and high-speed nanoindentation mapping techniques. While a highly heterogeneous microstructure is present in the as-deposited material, annealing results in a more uniform grain size, an increase in the fractions of twin and twin-related boundaries and a decrease in the density of geometrically necessary dislocations and low angle grain boundaries. The relative contributions of grain boundary hardening and work hardening are evaluated via hardness line profile analyses. The identification of oxide films along splat-splat interfaces suggests a potential additional factor contributing to local hardness. • Cold sprayed Cu materials for used nuclear fuel containers were studied using EBSD and nanoindentation. • Both microstructural and mechanical heterogeneity decreased after annealing. • The relative contributions of grain boundary hardening and work hardening were evaluated. • Oxide films along the interfaces of adjacent splats were identified. [ABSTRACT FROM AUTHOR]