A pore morphological study of gas-atomized Ti-6Al-4V powders by scanning electron microscopy and synchrotron X-ray computed tomography

Chen, G.; Zhou, Qingjun; Zhao, S.Y.; Yin, Jingou; Pan, Tan; Li, Z.F.; Ge, Yuan; Wang, Jian; Tang, Huiping

doi:10.1016/j.powtec.2018.02.053

Cited by 39 publications

(20 citation statements)

References 23 publications

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“…It must be noted here that the conditions that favor gas entrapment (higher porosity) also lead to a higher fraction of smaller particles during atomization. In the study by Gerling et al, the fraction of particles with d < 150 μm is 90%, and in the work of Chen et al, it amounts to 72%. In both cases, the yield of small particles is, indeed, significantly higher than that achieved in this study (a maximum of 58% in atom 3 ).…”

Section: Resultsmentioning

confidence: 99%

Gas atomization of γ‐TiAl Alloy Powder for Additive Manufacturing

2019

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The aim is, first, to optimize gas atomization of a γ‐TiAl alloy at the laboratory scale (atomized mass < 150 g) and, second, to investigate the microstructure of the produced powders. Gas atomization variables, such as the gas pressure and the melt temperature, are adjusted to produce the highest yield of particles with sizes smaller than 150 μm. The morphology and microstructure of these powders is characterized by scanning electron microscopy, as well as electron backscattered diffraction. The fine particles of interest are found to be single α2 polycrystals with spherical shape and negligible porosity. Overall, these particles meet the morphological requirements of raw powders for additive manufacturing powder‐based methods, provided the small loss of Al that takes place during melting is compensated by increasing the amount of this component in the starting alloy.

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Section: Resultsmentioning

confidence: 99%

Gas atomization of γ‐TiAl Alloy Powder for Additive Manufacturing

2019

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“…The coincidence of small pore diameters and the high sphericity clearly indicate gas entrapment in the feedstock powder as the reason for pore formation. [ 28–30 ] Thus, lack of fusion porosity as well as keyholing effects could be avoided in the process parameter window elaborated within the parameter study conducted.…”

Section: Resultsmentioning

confidence: 99%

On the Microstructural and Cyclic Mechanical Properties of Pure Iron Processed by Electron Beam Melting

et al. 2021

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Additive manufacturing (AM) processes such as electron beam melting (EBM) are characterized by unprecedented design freedom. Topology optimization and design of the microstructure of metallic materials are enabled by rapid progress in this field. The latter is of highest importance as many applications demand appropriate mechanical as well as functional material properties. For instance, biodegradable implants have to meet mechanical properties of human bone and at the same time guarantee adequate cytocompatibility and degradation rate. In this field, pure iron has come into focus in recent studies due to its low toxicity. Hierarchical microstructures resulting from the EBM solidification processes and intrinsic heat treatment, respectively, allow for an adjustment of the degradation behavior and may promote enhanced fatigue strength. Herein, commercially pure iron (cp‐Fe) is processed by EBM. Microstructural analysis as well as an evaluation of the cyclic mechanical material properties are conducted. The results are compared to a hot‐rolled (HR) reference material. A contradiction observed as the EBM‐processed cp‐Fe (EBM Fe) shows lower ultimate tensile strength under monotonic loading but improved fatigue properties compared to the HR Fe. It is revealed that such a unique behavior originates from prevailing microstructural features in the EBM as‐built condition.

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“…However, pore defects in additive manufactured products exhibit huge hidden dangers, which could significantly deteriorate both the mechanical and fatigue properties of the AM products [ 4 , 5 ]. Many investigations [ 4 , 5 , 6 , 7 , 8 ] have reported that most pores in additive manufacturing products originate from raw powders, and the pore defects in raw powders cannot be eliminated completely in the subsequent processing, such as with hot isostatic pressing (HIP). The characteristics of a powder strongly depend on the powder manufacturing technology.…”

Section: Introductionmentioning

confidence: 99%

“…Although some pore defects were observed in the powder prepared by the two processes, the characteristics of the pores are quite different [ 6 ]. In the last decades, many studies have been conducted on the pore characteristics in powders of different alloys [ 7 , 8 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Chen [ 6 ] found that the number and size of pores as well as the porosity and argon gas trapped in Ti-6Al-4V powders increase significantly with increasing particle size.…”

Section: Introductionmentioning

confidence: 99%

“…The pore characteristics in powders prepared by two processes were also compared. Chen [ 7 ] reported that GA powders demonstrate higher porosity than the corresponding PREP powders. However, there have been relatively few studies on the internal pores of PREP powder, in particular, the effects of PREP process parameters, such as rotation speed and alloy type, on the pore characteristics have not been discussed in detail.…”

Section: Introductionmentioning

confidence: 99%

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A Study on Internal Defects of PREP Metallic Powders by Using X-ray Computed Tomography

et al. 2021

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In this study, the distribution, proportion and characteristics of internal defects in three kinds of powders of Ti-6Al-4V, 316-steel and Co-29Cr-6Mo alloys, produced by the plasma rotating electrode process (PREP) at various rotation speeds, are characterized by using both scanning electron microscopy (SEM) and synchrotron X-ray computed tomography (CT). The results show that in the powder of a given alloy, internal pores are formed more easily in coarse particles than in fine powder during PREP. The proportion of powder with pores can be reduced by appropriately increasing the rotation speed. In addition, the composition of an alloy has a great influence on the defect formation.

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A pore morphological study of gas-atomized Ti-6Al-4V powders by scanning electron microscopy and synchrotron X-ray computed tomography

Cited by 39 publications

References 23 publications

Gas atomization of γ‐TiAl Alloy Powder for Additive Manufacturing

Gas atomization of γ‐TiAl Alloy Powder for Additive Manufacturing

On the Microstructural and Cyclic Mechanical Properties of Pure Iron Processed by Electron Beam Melting

A Study on Internal Defects of PREP Metallic Powders by Using X-ray Computed Tomography

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