| Résumé | In our previous studies, an increase in deposition efficiency (DE) was observed when 316L stainless steel was blended into commercial purity Fe to cold spray fabricate metal-metal composite implants. To better understand the mechanism of such improvement, a systematic research towards the DE was performed. In this study, two sizes of Fe and 316L powders (Fe large, Fe small, 316L large, 316L small) were used as the feedstock, and they were binarily mixed into four groups of Fe/316L mixtures (Fe small/316L large, Fe large/316L large, Fe small/316L small, Fe large/316L small) with three feedstock 316L fractions (10 wt.%, 20 wt.%, and 50 wt.%). The DEs of the single component powders and mixed powders were measured and discussed. Results show that the four binary Fe/316L mixtures exhibit different DE characteristics as a function of the feedstock 316L wt.%, and in particular, small size mixtures (Fe small/316L large, Fe small/316L small) have an improved DE relative to the single component Fe. The difference is explained by the particle-particle interactions (i.e. tamping and retention) upon impact, which only occur in small size mixtures. Results also show that changing cold spray process parameters (feed rate, stand-off distance, gun travel speed, gas temperature/pressure) does not affect the particle-particle interactions. |
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