Design and analysis of additive manufacturedbimodal structures obtained by cold spray deposition

Additive manufacturing potential of cold spray technology was used to fabricate freestanding samples of a copper alloy. Different volume fractions of micro and nanocrystalline powder particles were used to obatin a bimodal structure with heterogeneous arrangement of crystalline phases. The effects of volume fractions of each phase were investigated on the microstructural arrangement, porosity, microhardness, residual stresses, and mechanical strength of the deposited materials. A series of finite element simulations were developed and validated by experimental data to describe the influence of volume fraction, morphology, and spatial distribution of the phases on the global strength of the samples under tensile loading. The obtained results evidence the possibility of tailoring the mechanical response of freestanding cold spray deposits, adopting a heterogeneous phase structure. Optimized fabrication parameters and post-processing strategies should be studied to further enhance the performance of the designed bimodal materials and overcome the intrinsic brittleness of cold spray deposits.