Understanding Particle–Particle Interactions from Deposition Efficiencies in Cold Spray of Mixed Fe/316L Powders with Different Particle Size Combinations

摘要

In this study, Fe and 316L powders with two different particle sizes were used as the feedstock. They were also premixed using different mixing ratios and combinations: (i) either 316L or Fe powder with large particles blended with small ones and (ii) a blend of 316L and Fe powder using three particle size combinations. Both single-component and mixed powders were deposited by cold spray, and the deposition efficiencies (DEs) were calculated and discussed. The results show that the DE of a mixture of large and small particles of the same powder follows the Rule of Mixtures, whereas the variation of the DE of the 316L and Fe mixture depends on the particle size combinations; specifically, mixtures with smaller-sized particles show better DEs than the respective Fe powder. The difference in the DEs of different Fe/316L mixtures can be explained by the particle–particle interactions (i.e., tamping and retention) upon impact. In addition, a relationship between the average particle size and density is proposed to determine the occurrence of particle–particle interactions in cold spray of mixed generic powders. The industrial significance of the knowledge of particle–particle interactions is finally explained in the context of the fabrications of metal matrix composites.