Effect of heat treatment on the inherent anisotropy of cold sprayed copper deposits

In the present investigation, the effect of post-spray heat treatment (PSHT) on the microstructural and mechanical anisotropies of cold spray (CS) Cu deposits was investigated. The electron back-scattered diffraction and nanoindentation techniques were employed to characterize the microstructure and micromechanical properties in the cross-sectional (v-face) and parallel direction (p-face) to the surface following PSHT. Tensile tests were performed at various loading angles to identify the effect of PSHT on the in-plane tensile anisotropic behavior. It is revealed that microstructural anisotropy exists in both the as-sprayed and annealed CS deposits. And PSHT can effectively reduce the micromechanical anisotropy between the v-face and p-face. Tensile results show that the strong anisotropy of in-plane tensile strength can be moderated with PSHT. However, its effect on elongation anisotropy is quite limited, and the anisotropy is greatly increased at 700 °C. The existence of parallel multiple passes during CS remains the main factor hampering the further modification of the inherent in-plane tensile anisotropy especially elongation anisotropy.