Universal scaling laws of keyhole stability and porosity in 3D printing of metals

Abstract We leverage ultrahigh-speed synchrotron x-ray imaging and high-fidelity multiphysics modeling to identify strikingly simple yet universal scaling laws for keyhole stability and porosity in metal three-dimensional (3D) printing. The laws apply broadly and remain accurate for different materials, processing conditions, and printing machines. We define a new dimensionless number, the Keyhole number, to predict aspect ratio of a keyhole and the morphological transition from stable at low Keyhole number to chaotic at high Keyhole number. Furthermore, we discover inherent correlation between keyhole stability and porosity formation in metal 3D printing. By reducing the dimensions of the formulation of these challenging problems, the compact scaling laws will aid process optimization and defect elimination during metal 3D printing, and potentially lead to a quantitative predictive framework.

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Universal scaling laws of keyhole stability and porosity in 3D printing of metals

Nature Communications ◽

10.1038/s41467-021-22704-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Zhengtao Gan ◽

Orion L. Kafka ◽

Niranjan Parab ◽

Cang Zhao ◽

Lichao Fang ◽

...

Keyword(s):

3D Printing ◽

Process Optimization ◽

Scaling Laws ◽

Three Dimensional ◽

Dimensionless Number ◽

Monitoring And Control ◽

Vast Number ◽

Universal Scaling ◽

Metal 3D Printing ◽

And Control

AbstractMetal three-dimensional (3D) printing includes a vast number of operation and material parameters with complex dependencies, which significantly complicates process optimization, materials development, and real-time monitoring and control. We leverage ultrahigh-speed synchrotron X-ray imaging and high-fidelity multiphysics modeling to identify simple yet universal scaling laws for keyhole stability and porosity in metal 3D printing. The laws apply broadly and remain accurate for different materials, processing conditions, and printing machines. We define a dimensionless number, the Keyhole number, to predict aspect ratio of a keyhole and the morphological transition from stable at low Keyhole number to chaotic at high Keyhole number. Furthermore, we discover inherent correlation between keyhole stability and porosity formation in metal 3D printing. By reducing the dimensions of the formulation of these challenging problems, the compact scaling laws will aid process optimization and defect elimination during metal 3D printing, and potentially lead to a quantitative predictive framework.

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X-ray imaging with ultra-small-angle X-ray scattering as a contrast mechanism

Journal of Applied Crystallography ◽

10.1107/s0021889804016073 ◽

2004 ◽

Vol 37 (5) ◽

pp. 757-765 ◽

Cited By ~ 28

Author(s):

L. E. Levine ◽

G. G. Long

Keyword(s):

Small Angle ◽

Imaging Technique ◽

Three Dimensional ◽

Sample Volume ◽

Contrast Imaging ◽

X Ray ◽

X Ray Scattering ◽

X Ray Imaging ◽

Contrast Mechanism ◽

Ray Scattering

A new transmission X-ray imaging technique using ultra-small-angle X-ray scattering (USAXS) as a contrast mechanism is described. USAXS imaging can sometimes provide contrast in cases where radiography and phase-contrast imaging are unsuccessful. Images produced at different scattering vectors highlight different microstructural features within the same sample volume. When used in conjunction with USAXS scans, USAXS imaging provides substantial quantitative and qualitative three-dimensional information on the sizes, shapes and spatial arrangements of the scattering objects. The imaging technique is demonstrated on metal and biological samples.

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Quantitative study of fast non-local means-based denoising filter in chest X-ray imaging with lung nodule using three-dimensional printing

Optik ◽

10.1016/j.ijleo.2018.10.118 ◽

2019 ◽

Vol 179 ◽

pp. 1180-1188 ◽

Cited By ~ 1

Author(s):

Jina Shim ◽

Myonggeun Yoon ◽

Youngjin Lee

Keyword(s):

Quantitative Study ◽

Lung Nodule ◽

Three Dimensional ◽

Three Dimensional Printing ◽

X Ray ◽

Local Means ◽

X Ray Imaging ◽

Chest X Ray ◽

Non Local ◽

Dimensional Printing

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Interfacial Structure Control and Three-Dimensional X-ray Imaging of an Epoxy Monolith Bonding System with Surface Modification

Langmuir ◽

10.1021/acs.langmuir.0c01481 ◽

2020 ◽

Vol 36 (37) ◽

pp. 10923-10932

Author(s):

Nanako Sakata ◽

Yoshihiro Takeda ◽

Masaru Kotera ◽

Yasuhito Suzuki ◽

Akikazu Matsumoto

Keyword(s):

Surface Modification ◽

Three Dimensional ◽

Interfacial Structure ◽

X Ray ◽

Structure Control ◽

Bonding System ◽

X Ray Imaging

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Three Dimensional X-Ray Computed Tomography in Materials Science

MRS Bulletin ◽

10.1557/s0883769400066525 ◽

1988 ◽

Vol 13 (1) ◽

pp. 13-18 ◽

Cited By ~ 27

Author(s):

J.H. Kinney ◽

Q.C. Johnson ◽

U. Bonse ◽

M.C. Nichols ◽

R.A. Saroyan ◽

...

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Sample Preparation ◽

Visible Light ◽

Three Dimensional ◽

Materials Characterization ◽

Imaging Technology ◽

X Ray ◽

X Ray Imaging ◽

Visible Light Imaging

Imaging is the cornerstone of materials characterization. Until the middle of the present century, visible light imaging provided much of the information about materials. Though visible light imaging still plays an extremely important role in characterization, relatively low spatial resolution and lack of chemical sensitivity and specificity limit its usefulness.The discovery of x-rays and electrons led to a major advance in imaging technology. X-ray diffraction and electron microscopy allowed us to characterize the atomic structure of materials. Many materials vital to our high technology economy and defense owe their existence to the understanding of materials structure brought about with these high-resolution methods.Electron microscopy is an essential tool for materials characterization. Unfortunately, electron imaging is always destructive due to the sample preparation that must be done prior to imaging. Furthermore, electron microscopy only provides information about the surface of a sample. Three dimensional information, of great interest in characterizing many new materials, can be obtained only by time consuming sectioning of an object.The development of intense synchrotron light sources in addition to the improvements in solid state imaging technology is revolutionizing materials characterization. High resolution x-ray imaging is a potentially valuable tool for materials characterization. The large depth of x-ray penetration, as well as the sensitivity of absorption crosssections to atomic chemistry, allows x-ray imaging to characterize the chemistry of internal structures in macroscopic objects with little sample preparation. X-ray imaging complements other imaging modalities, such as electron microscopy, in that it can be performed nondestructively on metals and insulators alike.

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High-Speed X-Ray Imaging of Diesel Injector Needle Motion

ASME 2009 Internal Combustion Engine Division Spring Technical Conference ◽

10.1115/ices2009-76032 ◽

2009 ◽

Cited By ~ 19

Author(s):

A. L. Kastengren ◽

C. F. Powell ◽

Z. Liu ◽

K. Fezzaa ◽

J. Wang

Keyword(s):

High Speed ◽

Three Dimensional ◽

Linear Increase ◽

Nozzle Geometry ◽

X Ray ◽

Needle Position ◽

X Ray Imaging ◽

Linear Oscillation ◽

Degree Of Convergence

Phase-enhanced x-ray imaging has been used to examine the geometry and dynamics of four diesel injector nozzles. The technique uses a high-speed camera, which allows the dynamics of individual injection events to be observed in real time and compared. Moreover, data has been obtained for the nozzles from two different viewing angles, allowing for the full three-dimensional motions of the needle to be examined. This technique allows the needle motion to be determined in situ at the needle seat and requires no modifications to the injector hardware, unlike conventional techniques. Measurements of the nozzle geometry have allowed the average nozzle diameter, degree of convergence or divergence, and the degree of rounding at the nozzle inlet to be examined. Measurements of the needle lift have shown that the lift behavior of all four nozzles consists of a linear increase in needle lift with respect to time until the needle reaches full lift and a linear decrease as the needle closes. For all four nozzles, the needle position oscillates at full lift with a period of 170–180 μs. The full-lift position of the needle changes as the rail pressure increases, perhaps reflecting compression of the injector components. Significant lateral motions were seen in the two single-hole nozzles, with the needle motion perpendicular to the injector axis resembling a circular motion for one nozzle and linear oscillation for the other nozzle. The two VCO multihole nozzles show much less lateral motion, with no strong oscillations visible.

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