“…Although such a powder ensures achieving homogenous MMC parts due to the proper host/guest attachment and the lack of non-attached (free) agglomerated guest particles, the decorating guest particles act as obstacles to the free flow of host particles and consequently, sacrifice the flowability. Proper selection of the recoater speed in PBF–AM processes could be a strategy to solve this issue when using such composite powder feedstocks [91]. Based on the above discussions, the composite powder system prepared by a relatively short milling time of 2 h (B2) is suggested as the best possible case for PBF–AM processes.…”
This research aims at evaluating the characteristics of the 5 wt.% B4C/Ti-6Al-4V composite powder feedstock prepared by two different categories of mechanical mixing for powder bed fusion (PBF) additive manufacturing (AM) of metal matrix composites (MMCs). Microstructural features, particle size, size distribution, sphericity, conditioned bulk density and flow behavior of the developed powders were examined. The flowability of the regularly mixed powders was significantly lower than that of the Ti-6Al-4V powder. However, the flowability of the ball-milled systems was a significant function of the milling time. The decrease in the flowability of the 2 h ball-milled powder compared to the Ti-6Al-4V powder was attributed to the mechanical interlocking and the entangling caused by the B4C particles fully decorating the Ti-6Al-4V particles. Although the flattened/irregular shape of powder particles in the 6 h milled system acted to reduce the flowability, the overall surface area reduction led to higher flowability than that for the 2 h milling case. Regardless of the mixing method, incorporation of B4C particles into the system decreased the apparent density of the Ti-6Al-4V powder. The composite powder obtained by 2 h of ball milling was suggested as the best possible condition, meeting the requirements of PBF–AM processes.
“…Although such a powder ensures achieving homogenous MMC parts due to the proper host/guest attachment and the lack of non-attached (free) agglomerated guest particles, the decorating guest particles act as obstacles to the free flow of host particles and consequently, sacrifice the flowability. Proper selection of the recoater speed in PBF–AM processes could be a strategy to solve this issue when using such composite powder feedstocks [91]. Based on the above discussions, the composite powder system prepared by a relatively short milling time of 2 h (B2) is suggested as the best possible case for PBF–AM processes.…”
This research aims at evaluating the characteristics of the 5 wt.% B4C/Ti-6Al-4V composite powder feedstock prepared by two different categories of mechanical mixing for powder bed fusion (PBF) additive manufacturing (AM) of metal matrix composites (MMCs). Microstructural features, particle size, size distribution, sphericity, conditioned bulk density and flow behavior of the developed powders were examined. The flowability of the regularly mixed powders was significantly lower than that of the Ti-6Al-4V powder. However, the flowability of the ball-milled systems was a significant function of the milling time. The decrease in the flowability of the 2 h ball-milled powder compared to the Ti-6Al-4V powder was attributed to the mechanical interlocking and the entangling caused by the B4C particles fully decorating the Ti-6Al-4V particles. Although the flattened/irregular shape of powder particles in the 6 h milled system acted to reduce the flowability, the overall surface area reduction led to higher flowability than that for the 2 h milling case. Regardless of the mixing method, incorporation of B4C particles into the system decreased the apparent density of the Ti-6Al-4V powder. The composite powder obtained by 2 h of ball milling was suggested as the best possible condition, meeting the requirements of PBF–AM processes.
“…In recent years, Hybrid AMconventional manufacturing processes are emerging as a viable way to overcome the build limitations of AM, thus enhancing the functionally and expanding reach of the AM technology [18,19]. Hybrid manufacturing processes pose a significant technological advance, allowing for component repairs [20][21][22][23], production of bimaterials [24][25][26][27][28], and manufacturing of large components with intricate designs [29][30][31][32][33]. Hybrid manufacturing techniques, consisting of both powder bed fusion and wire arc AM hold a promise to result in a manufacturing method which marks the benefits of both worlds, i.e.…”
The implementation of additive manufacturing techniques in the production of mission critical structural components is challenged by its low throughput and limited build envelope. In recent years, hybrid production methods are emerging to bridge between the build volume and high throughput of conventional production methods and the design freedom enabled by additive manufacturing. The repeatability of material properties and the quality of the interface between the additive manufactured and wrought material are crucial for the adoption of hybrid manufacturing techniques by the industry. Here, the tensile behavior and fracture toughness of a hybrid Ti-6Al-4V alloy are examined in detail. Ti-6Al-4V pre-forms were built onto a wrought Ti-6Al-4V start-plate and extracted via milling. Compact tension and uniaxial tension specimens extracted from the hybrid pre-forms demonstrated good fracture and properties with no preference for crack growth in neither the AM nor wrought materials. Microstructural characterization revealed a 40 mm transition layer into the wrought material which ends abruptly with no evidence of a gradually decaying heat-affected zone. The hybrid manufacturing approach studied here expands the current limitations of large-scale critical components with fine features and allow such structures to be produced with a higher throughput.
Section: Powder Bed Hybrid Additive Manufacturingmentioning
confidence: 99%
“…Maraging steels, typically containing Fe-65%, Ni-18%, Co-8%, are widely used in the tool and die industry due to their high specific strength, high fracture toughness and weldability. They are used for many tooling applications including plastic injection molding, high pressure diecasting, stumping, and extrusion dies [35,37].…”
Section: Maraging and Tool Steelsmentioning
confidence: 99%
“…Investigation of hybrid additive manufacturing of maraging and tool steel has been already reported by several papers [37][38][39]49,61,65]. SLM / DMLS was used for 3D printing.…”
Hybrid additive manufacturing is a relatively modern trend in the integration of different additive manufacturing techniques in the traditional manufacturing production chain. Here the AM-technique is used for producing a part on another substrate part, that is manufactured by traditional manufacturing like casting or milling. Such beneficial combination of additive and traditional manufacturing helps to overcome well-known issues, like limited maximum build size, low production rate, insufficient accuracy, and surface roughness. The current paper is devoted to the classification of different approaches in the hybrid additive manufacturing of steel components. Additional discussion is related to the benefits of Powder Bed Fusion (PBF) and Direct Energy Deposition (DED) approaches for hybrid additive manufacturing of steel components.* e-mail: vvp@technion.ac.il Rev. 7, 6 (2020) This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Manufacturing
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