A5064482357- Additive Manufacturing Materials and Processes
- Additive Manufacturing and 3D Printing Technologies
- Welding Techniques and Residual Stresses
- Laser Material Processing Techniques
- Laser-induced spectroscopy and plasma
- Advanced X-ray and CT Imaging
- Cellular and Composite Structures
- Material Dynamics and Properties
- High Entropy Alloys Studies
- Nanopore and Nanochannel Transport Studies
- Mechanical Engineering and Vibrations Research
- Machine Learning in Materials Science
- Corrosion Behavior and Inhibition
- Industrial Vision Systems and Defect Detection
- Nanoporous metals and alloys
- Nuclear Materials and Properties
- Aerogels and thermal insulation
- Microfluidic and Capillary Electrophoresis Applications
- Mesoporous Materials and Catalysis
- Particle Dynamics in Fluid Flows
- Solidification and crystal growth phenomena
- Advanced battery technologies research
- Forecasting Techniques and Applications
- Fluid Dynamics and Thin Films
- Theoretical and Computational Physics
Argonne National Laboratory
2016-2024
Tsinghua University
2020-2024
Chinese Academy of Tropical Agricultural Sciences
2023
Hainan University
2023
Tropical Crops Genetic Resources Institute
2023
Sanya University
2023
Aerospace Research Institute of Materials and Processing Technology
2020-2022
Ministry of Education of the People's Republic of China
2022
Imperial College London
2021
Carnegie Mellon University
2021
We used ultrahigh-speed synchrotron x-ray imaging to quantify the phenomenon of vapor depressions (also known as keyholes) during laser melting metals practiced in additive manufacturing. Although expected from welding and inferred postmortem cross sections fusion zones, direct visualization keyhole morphology dynamics with high-energy x-rays shows that (i) keyholes are present across range power scanning velocity powder bed fusion; (ii) there is a well-defined threshold conduction mode...
We employ the high-speed synchrotron hard X-ray imaging and diffraction techniques to monitor laser powder bed fusion (LPBF) process of Ti-6Al-4V in situ real time. demonstrate that many scientifically technologically significant phenomena LPBF, including melt pool dynamics, ejection, rapid solidification, phase transformation, can be probed with unprecedented spatial temporal resolutions. In particular, keyhole pore formation is experimentally revealed high The solidification rate...
Laser powder bed fusion is a dominant metal 3D printing technology. However, porosity defects remain challenge for fatigue-sensitive applications. Some associated with deep and narrow vapor depressions called keyholes, which occur under high-power, low-scan speed laser melting conditions. High-speed x-ray imaging enables operando observation of the detailed formation process pores in Ti-6Al-4V caused by critical instability at keyhole tip. We found that boundary regime power-velocity space...
Abstract Laser powder bed fusion (LPBF) is a 3D printing technology that can print metal parts with complex geometries without the design constraints of traditional manufacturing routes. However, printed by LPBF normally contain many more pores than those made conventional methods, which severely deteriorates their properties. Here, combining in-situ high-speed high-resolution synchrotron x-ray imaging experiments and multi-physics modeling, we unveil dynamics mechanisms pore motion...
Melt flow plays a critical role in laser metal additive manufacturing, yet the melt behavior within pool has never been explicitly presented. Here, we report in-situ characterization of melt-flow dynamics every location entire manufacturing by populous and uniformly dispersed micro-tracers through high-resolution synchrotron x-ray imaging. The location-specific patterns different regions are revealed quantified under both conduction-mode depression-mode melting. physical processes at...
Size and shape of a melt pool play critical role in determining the microstructure additively manufactured metals. However, it is very challenging to directly characterize size beneath surface during additive manufacturing process. Here, we report direct observation quantification variation laser powder bed fusion (LPBF) process under constant input energy density by in-situ high-speed high-energy x-ray imaging. We show that can undergo different melting regimes both dimension volume have...
The high-speed synchrotron X-ray imaging technique was synchronized with a custom-built laser-melting setup to capture the dynamics of laser powder-bed fusion processes in situ. Various significant phenomena, including vapor-depression and melt-pool powder-spatter ejection, were captured high spatial temporal resolution. Imaging frame rates up 10 MHz used rapid changes these highly dynamic phenomena. At same time, relatively slow employed large-scale during process. This experimental...
The capability of producing complex, high performance metal parts on demand has established laser powder bed fusion (LPBF) as a promising additive manufacturing technology, yet deeper understanding the laser-material interaction is crucial to exploit potential process. By simultaneous in-situ synchrotron x-ray and schlieren imaging, we probe directly interconnected fluid dynamics vapour jet formed by depression it produces in melt pool. combined imaging shows formation stable plume over...
A high-speed synchrotron X-ray imaging technique was used to investigate the binder jetting additive manufacturing (AM) process. commercial printer with droplet-on-demand ink-jet print-head print single lines on powder beds. The printing process recorded in real time using imaging. droplets showed distinct elongated shape spherical head, long tail, and three five trailing satellite droplets. Significant drift observed between impact points of main droplet bed caused movement ejection...
In laser-based welding and additive manufacturing, the interaction of laser with metal leads to formation a cavity known as keyhole, which can fluctuate unstably during process. This work significantly advances our understanding laser-induced keyholes their dynamics, by combining state-of-the-art dynamic x-ray radiography multiphase, multiphysics modeling. Numerical simulations keyhole morphologies are validated experiment, then leveraged predict transient nonuniform distributions...
Powder-blown laser additive manufacturing adds flexibility, in terms of locally varying powder materials, to the ability building components with complex geometry. Although process is promising, porosity common a built component, hence decreasing fatigue life and mechanical strength. The understanding physical phenomena during interaction beam powder-blown deposition limited requires in-situ monitoring capture influences parameters on flow, absorptivity energy into substrate, melt pool...
Powder spreading is a key step in the powder-bed-based additive manufacturing process, which determines quality of powder bed and, consequently, affects manufactured part. However, behavior under condition still not clear, largely because lack particle-scale experimental study. Here, we studied dynamics during process by using in-situ high-speed high-energy x-ray imaging. Evolution repose angle, slope surface speed, roughness, and clusters at front were revealed quantified. Interactions...
Spattering has been a problem in metal processing involving high-power lasers, like laser welding, machining, and recently, additive manufacturing. Limited by the capabilities of situ diagnostic techniques, typically imaging with visible light or laboratory x-ray sources, comprehensive understanding laser-spattering phenomenon, particularly extremely fast spatters, not achieved yet. Here, using MHz single-pulse synchrotron-x-ray imaging, we probe spattering behavior Ti-6Al-4V micrometer...
Additive manufacturing, called 3D printing, has become ubiquitous in classrooms, laboratories, and research centers. While printing with plastics revolutionized prototyping modeling, it is now possible to fabricate metal parts devices directly from computer models by fusing particles together high-intensity lasers. This review focusses on the flow of heat material high temperature environment, instabilities that arise, tools control them.
Solidification or hot cracks are commonly observed defects in a number of metal alloys and may lead to deterioration additively manufactured parts quality. In this study, ultra-high-speed x-ray radiography experiments enable the observation characterization bundles hot-cracks that form monobloc AA6061 substrate. The crack related meltpool characteristics pore formation. Crack propagation rate is also presented for case initiates from pore. Two types relevant formation described, namely...