“…More to the point, satellites are commonly observed defects found within atomized particulate feedstocks for powder metallurgy processes and MAM processing [ 40 ]. During atomization, satellites develop through two primary pathways [ 41 ].…”
Section: Resultsmentioning
confidence: 99%
“…Still, Cu 2 was shown to have a greater density of satellites present, which is known to influence the in-flight dynamics of particles during cold spray processing. More to the point, satellites are commonly observed defects found within atomized particulate feedstocks for powder metallurgy processes and MAM processing [40]. During atomization, satellites develop through two primary pathways [41].…”
The surface roughness of additively manufactured (AM) components can have deleterious effects on the properties of the final part, such as corrosion resistance and fatigue life. Modification of the surface finish or parts produced by AM processes, such as cold spray, through methods such as mass finishing, can help to mitigate some of these issues. In this work, the surface evolution of as-produced copper cold sprayed material consolidations was studied through mass finishing. Three different copper powders attained by different production methods and of different sizes were used as feedstock. The surface topography of the cold spray deposits was measured as a function of the mass finishing time for the three copper cold spray samples and analyzed in terms of relative area and complexity, revealing an inverse correlation relating material removal rate and hardness/strength of the cold sprayed deposits. The material removal rate was also affected by the quality of the cold spray deposition, as defined by deposition efficiency (DE). Large initial drops in relative area and complexity are also likely due to the removal of loosely bonded powders at the start of mass finishing. Based on this study, the cold spray parameters that affect the rate of mass finishing have been explored.
“…More to the point, satellites are commonly observed defects found within atomized particulate feedstocks for powder metallurgy processes and MAM processing [ 40 ]. During atomization, satellites develop through two primary pathways [ 41 ].…”
Section: Resultsmentioning
confidence: 99%
“…Still, Cu 2 was shown to have a greater density of satellites present, which is known to influence the in-flight dynamics of particles during cold spray processing. More to the point, satellites are commonly observed defects found within atomized particulate feedstocks for powder metallurgy processes and MAM processing [40]. During atomization, satellites develop through two primary pathways [41].…”
The surface roughness of additively manufactured (AM) components can have deleterious effects on the properties of the final part, such as corrosion resistance and fatigue life. Modification of the surface finish or parts produced by AM processes, such as cold spray, through methods such as mass finishing, can help to mitigate some of these issues. In this work, the surface evolution of as-produced copper cold sprayed material consolidations was studied through mass finishing. Three different copper powders attained by different production methods and of different sizes were used as feedstock. The surface topography of the cold spray deposits was measured as a function of the mass finishing time for the three copper cold spray samples and analyzed in terms of relative area and complexity, revealing an inverse correlation relating material removal rate and hardness/strength of the cold sprayed deposits. The material removal rate was also affected by the quality of the cold spray deposition, as defined by deposition efficiency (DE). Large initial drops in relative area and complexity are also likely due to the removal of loosely bonded powders at the start of mass finishing. Based on this study, the cold spray parameters that affect the rate of mass finishing have been explored.
“… Figure 4. Schematic showing the formation mechanisms of (a) internal pores and (b) three different kinds of satellites during the process of gas atomization. Reprinted with permission from [71,72]. …”
Laser-based additive manufacturing (LBAM) has shown great potential in the development of new metallic materials, especially in the design and fabrication of metal matrix composites (MMCs). Steel matrix composites (SMCs) as one MMC-type, have been successfully additively manufactured with full density and good performance. This article reviews emerging studies of LBAM-fabricated SMCs, starting from the methods of feedstock preparation including respective merits and challenges. The mechanisms of phase transformation, grain growth and texture development of the steel matrix, as well as the precipitation of reinforcements during rapid solidification inherent to LBAM are demonstrated. Microstructural features of SMCs with different matrix (austenitic, martensitic, duplex and ferritic) and reinforcement types are discussed. The interrelationship between the composition and physical properties of the composite powder, microstructures and mechanical properties of SMCs are disclosed and the involved strengthening mechanisms are discussed. Lastly, conclusions and outlook focusing on emerging trends of LBAM-fabricated SMCs are presented.
“…As shown in blue in Figure 3(1b,2a), the presence of satellites is also highly limited in both Al-Fe-Si-Cr-Ni compositions. Turbulence in the near-nozzle region that can occur during argon gas outflow at sonic velocity can generate the formation of tiny, already solidified particles, which can adhere to larger particles due to surface tension forces creating "outer satellites" or to molten droplets forming "embedded satellites" [21]. The poor occurrence of this defect in the analysed systems can be explained by the high viscosity of the molten stream due to the conspicuous presence of Fe in both alloys, which allows a slower, more stable gas atomisation process and the limited formation of ultra-fine particles.…”
Rapid solidification techniques, such as gas atomisation, have been widely implemented in metallic alloys/composites to increase solid solubility, avoid or mitigate segregation phenomena, and favour metastable phase formation to enhance performance. Particularly, gas atomisation can enhance the solid solubility of low diffusion coefficient elements like Fe, Ni, Mn, Zr, and Cr in the α-Al matrix, yielding metastable phases. As a result, Al alloys exhibit excellent strength at high temperatures. In this study, the AISI 304L alloy was employed to introduce Fe, Ni, and Cr elements into the AlSi10Mg alloy through gas atomisation, resulting in the formation of two distinct hypereutectic AlFe-based alloys: AlFe9Si8Cr2Ni and AlFe18Si8Cr5Ni2. Gas-atomised alloy powders were separated into different size fractions by sieving and characterised using X-ray diffraction, differential scanning calorimetry, optical microscopy, and scanning electron microscopy. Microstructural analyses revealed dendritic patterns with distinct phases, highlighting the influence of the alloying element content on the solidification processes. Furthermore, a synergic evaluation of the XRD and EDS analysis results allowed the identification of intermetallic phases and their distribution in the two systems.
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