Exploration of the Effects of Metallic Powder Handling and Storage Conditions on Flowability and Moisture Content for Additive Manufacturing Applications

Abstract

Metal powder-based additive manufacturing (AM) relies on consistently successful processing of feedstock powder, necessitating through-process predictability in powder properties and behavior. However, routine powder handling and storage may degrade powder performance by influencing flowability and moisture content through exposure to ambient conditions. Therefore, this study aimed to evaluate the effects of repeated environmental exposure on the flowability and moisture content of Al 5056 and Ta powders for AM applications. Using Carney Funnel flow tests, thermogravimetric analysis, and particle size/shape analysis, powder characterization helped elucidate powder property and behavioral changes with exposure. Results indicated inconsistent flowability and moisture content changes for both material types when exposure conditions were altered. Correlational statistics highlighted the most influential particle characteristics on powder behavior after exposure; particle morphology was most impactful for the semi-spherical Al 5056, whereas moisture content and particle size were most significant for the angular Ta. While exposure to laboratory conditions minimally changed powder performance in this study, caution is advised when handling and storing powders in more “extreme” environments. Powder users are urged to implement quality controls alongside powder characterization to pinpoint how specific powders should be treated, handled, and stored in a given environment for successful processing in AM.

A novel method of hydro-vacuum dispersion of metallurgical melts: research and implementation

“…It was determined that, as a result of the optimization of the mentioned parameters, in order to obtain −1 bar rarefaction in the hydro-vacuum dispersion chamber (Figure 1, position 8), in exchange for the supply of water at a rate of 0.029 m 3 s −1 into the circular collector channel (4) with a pressure of 16-20 bar used by us so far it will be enough to develop a speed of 0.022 m 3 s −1 and a pressure of 13.2 bar. The effectiveness of the mentioned solution is clearly proven by the results of the report on the acceleration rates of the melt particles absorbed/dispersed under the influence of the pressure drop and created rarefaction in the confuser-diffuser pair (5)(6)(7)(8), which is presented in Figure 7 in the form of diagrams.…”

“…The vertically sucked liquid metallic jet, extending through the zone of hydraulically rarefied funnel formed in the core of the cone-shaped water jet shell injected from under the semi-toroidal annular confuser (5), in the process of axial displacement and exit from the compression zone, under the influence of force hydromechanical impact narrows in cross-section (d 1 > d 2 ), accelerates, and then, due to elastic forces of acceleration expands again, accelerates, and in the consequence of excited powerful centrifugal-tangential tensile forces destroys, splashing in the dispersion chamber (8) with small shapeless drops. The process proceeds so quickly that the possibility of vapor accumulation and excessive pressure rise is completely excluded.…”

“…In each individual case, the equipment needs to be retooled, to change working nodes and their operating modes. In addition, in the large-scale production of powders (for example, the production of iron powder), operational management of the efficiency of the melt sputtering process, including stabilization of the conditions of formation into individual granules, long-term maintenance of operational properties, elimination of the problem of oxidation, gas saturation and reduction of pyroporosity, has remained an unsolved task until now [7][8][9]. As a result, the powders obtained by this method are inevitably subjected to additional sorting-mechanical crushing in an inert gas environment, as well as to further thermal, hydrogen-reducing treatment [10,11].…”

Laser‐Based Directed Energy Deposition Remanufacturing of Gray Cast Iron using Stainless Steel 316L and Inconel 625 Filler Materials

“…The high surface energy of the powder particles also captures moisture, introducing additional contaminants into the melt pool. [ 23 ] Additionally, the melt pool in powder DED primarily comprises the substrate with periodic incorporation of powder particles. During wire DED, the majority of the melt pool volume is formed from continuously melting wire.…”

Ongoing Challenges of Laser-Based Powder Bed Fusion Processing of Al Alloys and Potential Solutions from the Literature—A Review

“…Flow properties are influenced by several factors such as particle size distribution (PSD), powder morphology and storage conditions. Based on a comprehensive review conducted by Vock et al [ 30 ] and the most recently published papers, some general rules can be defined for the flow properties: increase with decreasing width of the PSD [ 33 , 34 , 35 , 36 ]; improve with coarser particles [ 33 , 34 , 36 ]; decrease with increasing moisture content until saturation with liquid [ 33 , 37 , 38 , 39 ]. …”