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The low deposition efficiency in directed energy deposition (DED) has prompted the reuse of powders that do not fuse to the builds to make additive manufacturing more sustainable. It is unknown, however, how the properties of the powder and deposited parts change as powders are continuously reused. In this study, AlSi10Mg was investigated for five deposition cycles in DED. Exposing AlSi10Mg powder to DED conditions changes the morphology, size, and flowability. The mechanical properties of AlSi10Mg DED parts decreased after the feedstock powder was reused one time. Notably, no additional significant changes were observed when the powder was further reused.

Additive manufacturing of Al alloys presents an opportunity to produce complex parts that leverage their high specific strength. This paper aims to study the effect of processing parameters on the fabrication of single tracks and thin walls using AlSi10Mg powder in L-DED. A processing window was identified to enable continuous single track deposition with a regular shape. Deposition of thin walls and single tracks were used as a guideline to deposit blocks. Blocks were deposited using L-DED, and the physical, microstructural, and mechanical properties of the samples were investigated. Results demonstrated that the morphology of the thin walls were a better indicator of the morphology of the block samples than single tracks were, and care must be taken when transitioning from depositing single tracks to bulk (thin walls and blocks) samples. Results from mechanical testing show slight inhomogeneity as a function of height within the build for elongation and ultimate tensile strength. Microhardness and yield strength, however, were mostly uniform throughout the build. Overall, the results of this study demonstrate that L-DED is suitable for depositing AlSi10Mg and obtaining mechanical properties superior to those achieved through casting.

Particulate reinforced aluminum-based metal matrix composites (Al MMCs) continue to be of interest, partly due to their low density, but also because of their ability to provide tailored property combinations, such as high specific stiffness, specific strength and creep resistance. This article provides a review on the progress that has been made in the field of particulate reinforced Al MMCs during the past decade, paying particular attention to the influence of size and spatial distributions of the Al alloy matrix grains and the reinforcing particles on the mechanical performance of the composites. In addition, the current state-of-the-art as well as the challenges facingAl MMCs that involve heat treatableAl alloys as the matrix are addressed. Finally, our recent findings related to B4C particulate reinforced 7xxx series Al alloy (Al-Zn-Mg) MMCs are also discussed. [ABSTRACT FROM AUTHOR]