47 results on '"Jianchao Ye"'
Search Results
2. A 3D nm-thin biomimetic membrane for ultimate molecular separation
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Y. Morris Wang, Jianchao Ye, Theodore F. Baumann, Thomas Voisin, Tongshuai Wang, Zhen Qi, Juergen Biener, Monika M. Biener, Sangil Kim, Marcus A. Worsley, Ich C. Tran, Siwei Liang, Joshua A. Hammons, and T. Braun
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Materials science ,Water transport ,Process Chemistry and Technology ,Permeance ,Permeation ,Ion ,Amorphous solid ,chemistry.chemical_compound ,Membrane ,chemistry ,Chemical engineering ,Mechanics of Materials ,General Materials Science ,Nanometre ,Electrical and Electronic Engineering ,Polysulfide - Abstract
Multi-functional membranes with high permeance and selectivity that can mimic nature's designs have tremendous industrial and bio-medical applications. Here, we report a novel concept of a 3D nanometer (nm)-thin membrane that can overcome the shortcomings of conventional membrane structures. Our 3D membrane is composed of two three-dimensionally interwoven channels that are separated by a continuous nm-thin amorphous TiO2 layer. This 3D architecture dramatically increases the surface area by 6000 times, coupled with an ultra-short diffusion distance through the 2–4 nm-thin selective layer that allows for ultrafast gas and water transport, ∼900 l m−2 h−1 bar−1. The 3D membrane also exhibits a very high ion rejection (R ∼ 100% for potassium ferricyanide) due to the combined size- and charge-based exclusion mechanisms. The combination of high ion rejection and ultrafast permeation makes our 3DM superior to the state-of-the-art high-flux membranes whose performances are limited by the flux-rejection tradeoff. Furthermore, its ultimate Li+ selectivity over polysulfide or gas can potentially solve major technical challenges in energy storage applications, such as lithium–sulfur or lithium–O2 batteries.
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- 2020
3. VTO_2021_APR_LLNL_Ye
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Jianchao Ye, E. Ramos, M. Wood, and S. Liang
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- 2021
4. Ultra-low-density digitally architected carbon with a strutted tube-in-tube structure
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Y. Morris Wang, Maira R. Cerón, Sanjit Bhowmick, Ling Liu, Juergen Biener, Monika M. Biener, Jip van Ham, James S. Oakdale, William L. Smith, Thomas Voisin, Jianchao Ye, Patrick Onck, Joseph Lefebvre, Leonardus Bimo Bayu Aji, John D. Roehling, and Micromechanics
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Structural material ,Materials science ,Mechanical Engineering ,chemistry.chemical_element ,Stiffness ,Topology (electrical circuits) ,General Chemistry ,Condensed Matter Physics ,Compression (physics) ,chemistry ,Mechanics of Materials ,medicine ,General Materials Science ,Composite material ,medicine.symptom ,Porous medium ,Nanoscopic scale ,Carbon ,Beam (structure) - Abstract
Porous materials with engineered stretching-dominated lattice designs, which offer attractive mechanical properties with ultra-light weight and large surface area for wide-ranging applications, have recently achieved near-ideal linear scaling between stiffness and density. Here, rather than optimizing the microlattice topology, we explore a different approach to strengthen low-density structural materials by designing tube-in-tube beam structures. We develop a process to transform fully dense, three-dimensional printed polymeric beams into graphitic carbon hollow tube-in-tube sandwich morphologies, where, similar to grass stems, the inner and outer tubes are connected through a network of struts. Compression tests and computational modelling show that this change in beam morphology dramatically slows down the decrease in stiffness with decreasing density. In situ pillar compression experiments further demonstrate large deformation recovery after 30–50% compression and high specific damping merit index. Our strutted tube-in-tube design opens up the space and realizes highly desirable high modulus–low density and high modulus–high damping material structures. A nanoscale tube-in-tube sandwich structure is generated by a two-step templating-pyrolysis process, which strengthens the log-pile carbon architecture and slows down the decrease of stiffness with decreasing density.
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- 2021
5. Tensile properties, strain rate sensitivity, and activation volume of additively manufactured 316L stainless steels
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Chandrika Kamath, Thomas Voisin, T. Braun, Joseph T. McKeown, Jianchao Ye, Y. Morris Wang, Wayne E. King, and Zan Li
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010302 applied physics ,Materials science ,Mechanical Engineering ,02 engineering and technology ,Plasticity ,Strain rate ,021001 nanoscience & nanotechnology ,01 natural sciences ,Grain size ,Mechanics of Materials ,0103 physical sciences ,Ultimate tensile strength ,General Materials Science ,Grain boundary ,Deformation (engineering) ,Composite material ,0210 nano-technology ,Burgers vector ,Tensile testing - Abstract
The tensile properties of additively manufactured (AM) metals and alloys are among the most important variables that impact the potential applications of these materials. Here we examine and report on the tensile properties of AM 316L stainless steels fabricated by the laser powder-bed-fusion (L-PBF) technique, via twelve sets of optimized laser processing parameters that produce materials with density >98.8 ± 0.10%. A heterogeneous microstructure is observed in all L-PBF samples, including microscopic features such as dislocations, cellular walls, elemental segregations, local misorientations, impurities, precipitates, and a large fraction of low-angle grain boundaries (2-10°, ∼40–60%). The derived average grain size defined by high-angle grain boundaries (>10°) is ∼30–50 μm. Tensile testing reveals a yield strength ranging from 552 to 635 MPa and a tensile-elongation-to-failure (TEF) of 0.09–0.42 for directly-printed samples, whereas these values are 592–690 MPa and 0.29–0.50 for samples machined from the as-built rectangular thin plates. In all samples, we observe a variation of tensile yield strength within ∼15% but not the TEF, suggesting marginal microstructural changes despite a wide range of laser processing parameters. The large scatter of TEF in directly-printed samples originates from the sensitivity of thin gauge geometry (∼2 mm2 cross-section area) to the built-in flaws. We measured a substantially higher strain rate sensitivity (m∼0.02–0.03) of L-PBF 316L compared to the coarse-grained counterparts (∼0.006), together with a small activation volume of ∼20–30b3 (where b is the Burgers vector of 316L). These deformation kinetics parameters suggest that the tensile plasticity of L-PBF 316L is controlled by a much finer microstructural length scale than the measured grain size, consistent with the high strength and juxtaposed nano- to macro-structures seen in these materials. Strategies to optimize the tensile properties of AM materials are discussed.
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- 2019
6. Vehicle Technologies Office Quarterly Report (FY21Q2)
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Jianchao Ye
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- 2021
7. Chemical recovery of spent copper powder in laser powder bed fusion
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Alistair Speidel, Leonidas Gargalis, Jianchao Ye, Manyalibo J. Matthews, Adriaan Spierings, Richard Hague, Adam T. Clare, and James W. Murray
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Powder recovery ,Laser powder bed fusion ,Powder reprocessing ,Powder recycling ,Chemical etching ,Porosity ,Biomedical Engineering ,General Materials Science ,Engineering (miscellaneous) ,Industrial and Manufacturing Engineering - Abstract
In laser powder bed fusion (LPBF), recovered unfused powder from the powder bed often degrades upon sequential processing through mechanisms like thermal oxidation and particle satelliting from ejected weld spatters and particle-laser interactions. Given the sensitivity of LPBF performance and build quality to powder properties, spent powder is generally discarded after a few build cycles, especially for materials that are sensitive towards surface oxidation. This increases feedstock material costs, as well as costs associated with machine downtime during powder replacement. Here, a new method to chemically reprocess spent LPBF metal powder is demonstrated under ambient conditions, using a heavily oxidised Cu powder feedstock recovered from prior LPBF processing as a model material. This is compared to an equivalent virgin Cu powder. The near-surface powder chemistry has been analysed, and it is shown that surface oxide layers present on spent Cu powder can be effectively reset after rapid reprocessing (from 5 to 20 min). Diffuse reflectance changes on etching, reducing for gas-atomised virgin Cu powder due to the formation of anisotropic etch facets, and increasing for heavily oxidised spent Cu as the highly absorptive oxide layers are removed. The mechanism of powder degradation for moisture sensitive materials like Cu has been correlated to the degradation of LPBF deposits, which manifests as widespread and extensive porosity. This extensive porosity is largely eliminated after reprocessing the spent Cu powder. Chemically etched spent powder is therefore demonstrated as a practical feedstock in LPBF in which track density produced is comparable to virgin powder., Additive Manufacturing, 52, ISSN:2214-8604
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- 2022
8. 2020 Vehicle Technology Office Annual Progress Report from Jianchao Ye
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Jianchao Ye
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- 2020
9. Vehicle Technology Office (Quarterly Report, FY20 Q2)
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Jianchao Ye
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- 2020
10. Printing of All Solid-State Lithium Batteries (BMR FY20Q1 Task 4)
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Jianchao Ye
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Materials science ,chemistry ,Nuclear engineering ,All solid state ,chemistry.chemical_element ,Lithium ,Task (project management) - Published
- 2020
11. Amorphization as a Pathway to Fast Charging Kinetics in Atomic Layer Deposition-Derived Titania Films for Lithium Ion Batteries
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Patrick Shea, Brandon C. Wood, Jianchao Ye, Monika M. Biener, Michael Bagge-Hansen, Y. Morris Wang, Andreas C. Baumgaertel, Juergen Biener, and Stanimir Bonev
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Materials science ,Fast charging ,General Chemical Engineering ,Kinetics ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Ion ,Atomic layer deposition ,chemistry ,Chemical engineering ,Materials Chemistry ,Lithium ,0210 nano-technology ,Power density - Abstract
Safe, reliable materials with fast charging kinetics are required to increase the power density of batteries in electric vehicles. One potential avenue for improving kinetics involves disturbing th...
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- 2018
12. NiAu Single Atom Alloys for the Non-oxidative Dehydrogenation of Ethanol to Acetaldehyde and Hydrogen
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Jianchao Ye, Antonios Trimpalis, Maria Flytzani-Stephanopoulos, Junjun Shan, Zhen Qi, Sufeng Cao, Juergen Biener, Jilei Liu, and Georgios Giannakakis
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Materials science ,Hydrogen ,Alloy ,Inorganic chemistry ,Acetaldehyde ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Activation energy ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Copper ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,engineering ,Dehydrogenation ,0210 nano-technology ,Selectivity - Abstract
Gold is examined here as an alternative to copper for the selective dehydrogenation of ethanol to acetaldehyde and hydrogen. Despite its high selectivity, gold is only active at temperatures higher than 250 °C for this reaction. We demonstrate that addition of a small amount of Ni on either supported or unsupported Au surfaces induces resistance to sintering, along with a beneficial effect on the catalytic activity. NiAu alloys prepared here with Ni as the minority component to the limit of atomic dispersion in the gold surfaces, catalyze the reaction beginning below 150 °C. A significant decrease of the apparent activation energy from 96 ± 3 kJ/mol for the monometallic Au to 59 ± 5 kJ/mol for the alloy was found. The Ni dispersion and concentration as a function of gas environment was followed by in situ DRIFTS and by XPS. The stability of the catalyst morphology was investigated through post-reaction microscopy imaging and long-term stability tests under reaction conditions. As shown via dynamic reaction experiments, acetaldehyde and H2 were selectively produced up to 280 °C. A small drop of selectivity at higher temperatures is attributed to the formation of Ni clusters, as proven by CO-DRIFTS on the used sample. Comparison with samples of higher Ni loading, where Ni clusters are formed, clearly shows that they catalyze the undesired full decomposition of ethanol to CO, CH4, and H2.
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- 2018
13. Radiopaque Resists for Two-Photon Lithography To Enable Submicron 3D Imaging of Polymer Parts via X-ray Computed Tomography
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James S. Oakdale, Jianchao Ye, Jean-Baptiste Forien, Chuck Divin, Sourabh K. Saha, Jefferson Cuadra, Juergen Biener, William L. Smith, and Leonardus Bimo Bayu Aji
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Fabrication ,Materials science ,Microfluidics ,Metamaterial ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Multiphoton lithography ,01 natural sciences ,0104 chemical sciences ,law.invention ,Metrology ,Resist ,law ,General Materials Science ,0210 nano-technology ,Lithography ,Stereolithography - Abstract
Two-photon lithography (TPL) is a high-resolution additive manufacturing (AM) technique capable of producing arbitrarily complex three-dimensional (3D) microstructures with features 2-3 orders of magnitude finer than human hair. This process finds numerous applications as a direct route toward the fabrication of novel optical and mechanical metamaterials, miniaturized optics, microfluidics, biological scaffolds, and various other intricate 3D parts. As TPL matures, metrology and inspection become a crucial step in the manufacturing process to ensure that the geometric form of the end product meets design specifications. X-ray-based computed tomography (CT) is a nondestructive technique that can provide this inspection capability for the evaluation of complex internal 3D structure. However, polymeric photoresists commonly used for TPL, as well as other forms of stereolithography, poorly attenuate X-rays due to the low atomic number (Z) of their constituent elements and therefore appear relatively transparent during imaging. Here, we present the development of optically clear yet radiopaque photoresists for enhanced contrast under X-ray CT. We have synthesized iodinated acrylate monomers to formulate high-Z photoresist materials that are capable of forming 3D microstructures with sub-150 nm features. In addition, we have developed a formulation protocol to match the refractive index of the photoresists to the immersion medium of the objective lens so as to enable dip-in laser lithography, a direct laser writing technique for producing millimeter-tall structures. Our radiopaque photopolymer resists increase X-ray attenuation by a factor of more than 10 times without sacrificing the sub-150 nm feature resolution or the millimeter-scale part height. Thus, our resists can successfully replace existing photopolymers to generate AM parts that are suitable for inspection via X-ray CT. By providing the "feedstock" for radiopaque AM parts, our resist formulation is expected to play a critical role in enabling fabrication of functional polymer parts to tight design tolerances.
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- 2017
14. Additively manufactured hierarchical stainless steels with high strength and ductility
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Manyalibo J. Matthews, Thomas Voisin, Tien T. Roehling, Yin Zhang, Y. Morris Wang, Alex V. Hamza, Wen Chen, Zhi Zeng, Joseph T. McKeown, Melissa K. Santala, Philip J. Depond, Nicholas P. Calta, Ting Zhu, Zan Li, Ryan T. Ott, and Jianchao Ye
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010302 applied physics ,Austenite ,Orders of magnitude (temperature) ,Mechanical Engineering ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,01 natural sciences ,Mechanics of Materials ,0103 physical sciences ,General Materials Science ,Grain boundary ,Composite material ,Elongation ,Dislocation ,0210 nano-technology ,Ductility ,Crystal twinning - Abstract
Many traditional approaches for strengthening steels typically come at the expense of useful ductility, a dilemma known as strength-ductility trade-off. New metallurgical processing might offer the possibility of overcoming this. Here we report that austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibit a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels. High strength is attributed to solidification-enabled cellular structures, low-angle grain boundaries, and dislocations formed during manufacturing, while high uniform elongation correlates to a steady and progressive work-hardening mechanism regulated by a hierarchically heterogeneous microstructure, with length scales spanning nearly six orders of magnitude. In addition, solute segregation along cellular walls and low-angle grain boundaries can enhance dislocation pinning and promote twinning. This work demonstrates the potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications.
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- 2017
15. Selective non-oxidative dehydrogenation of ethanol to acetaldehyde and hydrogen on highly dilute NiCu alloys
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Cynthia M. Friend, Jilei Liu, Nare Janvelyan, Hang Li, Tobias Egle, Jianchao Ye, Monika M. Biener, Maria Flytzani-Stephanopoulos, Junjun Shan, and Juergen Biener
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Materials science ,Hydrogen ,Nanoporous ,Process Chemistry and Technology ,Inorganic chemistry ,Acetaldehyde ,Nanoparticle ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,7. Clean energy ,01 natural sciences ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Nickel ,chemistry ,Dehydrogenation ,0210 nano-technology ,Mesoporous material ,General Environmental Science - Abstract
The non-oxidative dehydrogenation of ethanol to acetaldehyde has long been considered as an important method to produce acetaldehyde and clean hydrogen gas. Although monometallic Cu nanoparticles have high activity in the non-oxidative dehydrogenation of ethanol, they quickly deactivate due to sintering of Cu. Herein, we show that adding a small amount of Ni (Ni0.01Cu − Ni0.001Cu) into Cu to form highly dilute NiCu alloys dramatically increases the catalytic activity and increases their long-term stability. The kinetic studies show that the apparent activation energy decreases from ∼70 kJ/mol over Cu to ∼45 kJ/mol over the dilute NiCu alloys. The improved performance is observed both for nanoparticles and nanoporous NiCu alloys. The improvement in the long-term stability of the catalysts is attributed to the stabilization of Cu against sintering. Our characterization data show that Ni is atomically dispersed in Cu. The comparison of the catalytic performance of highly dilute alloy nanoparticles with nanoporous materials is useful to guide the design of novel mesoporous catalyst architectures for selective dehydrogenation reactions.
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- 2017
16. Macroscopic 3D Nanoporosity Formation by Dry Oxidation of AgAu Alloys
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Austin J Akey, Nare Janvelyan, Jianchao Ye, David C. Bell, Andrew P. Magyar, Juergen Biener, Cédric Barroo, Efthimios Kaxiras, Branko Zugic, and Matthew M. Montemore
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Fabrication ,Materials science ,Nanoporous ,Diffusion ,Alloy ,Nanowire ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Corrosion ,Metal ,General Energy ,Chemical engineering ,visual_art ,visual_art.visual_art_medium ,engineering ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
3D nanoporous metals made by alloy corrosion have attracted much attention due to various promising applications ranging from catalysis and sensing to energy storage and actuation. In this work we report a new process for the fabrication of 3D open nanoporous metal networks that phenomenologically resembles the nano-Kirkendall hollowing process previously reported for Ag/Au nanowires and nanoparticles, with the difference that the involved length scales are 10–100 times larger. Specifically, we find that dry oxidation of Ag70Au30 bulk alloy samples by ozone exposure at 150 °C stimulates extremely rapid Ag outward diffusion toward the gas/alloy-surface interface, at rates at least 5 orders of magnitude faster than predicted on the basis of reported Ag bulk diffusion values. The micrometer-thick Ag depleted alloy region thus formed transforms into a 3D open nanoporous network morphology upon further exposure to methanol–O2 at 150 °C. These findings have important implications for practical applications of a...
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- 2017
17. Enhanced mechanical performance via laser induced nanostructure formation in an additively manufactured lightweight aluminum alloy
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Manyalibo J. Matthews, Caitlyn C. Cook, Tian T. Li, Scott K. McCall, Nicholas Teslich, Aiden A. Martin, Jonathan R. I. Lee, Michael H. Nielsen, Jianchao Ye, Ryan T. Ott, Alyssa A. Maich, Michael Thompson, Orlando Rios, Nicholas P. Calta, Trevor M. Willey, Joshua A. Hammons, Matthew F. Besser, and Hunter B. Henderson
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Nanostructure ,Materials science ,Alloy ,Intermetallic ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Microstructure ,Laser ,01 natural sciences ,0104 chemical sciences ,law.invention ,Casting (metalworking) ,law ,Tearing ,Ultimate tensile strength ,engineering ,General Materials Science ,Composite material ,0210 nano-technology - Abstract
To date, the primary focus of metal additive manufacturing (AM) research has been the development of strategies for fabricating complex architectures, reducing internal stress and optimizing microstructure. Traditional Al alloys have presented further challenges in this effort due to solidification cracking and complex laser coupling dynamics. To overcome these limitations, identification of novel alloys that exploit the rapid solidification conditions inherent in laser-based AM is required. In this work, laser-induced melting of an Al-8Ce-10Mg alloy is revealed to generate a nanoscale microstructure which results in improved hardness, tensile strength, and mitigated solidification cracking (e.g., hot tearing) in single laser tracks in as-cast material and laser powder bed fusion (LPBF)-fabricated components. In situ X-ray imaging shows the nanostructure arises from laser-induced melting of intermetallic particles embedded into the alloy during casting and then rapid resolidification of the molten material in ~ 400 µs. The formed Ce-rich nanostructures are highly resistant to thermal coarsening at 300 °C, as confirmed by microscopy and retention of tensile properties. These results pave the way for development of AM-specific Al alloys that possess the ability to form mechanically favorable nanostructures in fabricated components due to the rapid cooling inherent in LPBF.
- Published
- 2021
18. Exploring the relationship between solvent-assisted ball milling, particle size, and sintering temperature in garnet-type solid electrolytes
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Tae Wook Heo, Jose Ali Espitia, Rongpei Shi, Eric B. Duoss, Jianchao Ye, Xiaosi Gao, Brandon C. Wood, and Marissa Wood
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Materials science ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Sintering ,Ionic bonding ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry ,Chemical engineering ,Fast ion conductor ,Ionic conductivity ,Particle ,Lithium ,Particle size ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,0210 nano-technology ,Ball mill - Abstract
Garnet-type solid electrolytes, such as Li6.4La3Zr1.4Ta0.6O12 (LLZTO), are promising materials for solid-state batteries, but processing remains a challenge, in part due to the high sintering temperature required for densification. This temperature can be lowered by decreasing the initial particle size via solvent-assisted ball milling, but the relationship between solvent choice, particle properties, sintering behavior, and ionic conductivity is not well understood. In this work, we systematically explore these parameters, showing that milling in commonly used protic solvents, such as alcohols, effectively decreases the particle size but results in lithium loss (through Li+/H+ exchange) that leads to poor sintering. By contrast, milling in aprotic solvents with surfactant reduces the particle size to ~220 nm without lithium loss, enabling the fabrication of dense samples (5.1 g/cm3) with good ionic conductivity (0.43 mS/cm at 25 °C) at a lower sintering temperature (1000 °C). We compare ionic conductivities and activation energies for samples prepared with different particle sizes and sintering temperatures and use multiphase-field simulations to identify the mass transport and microstructural mechanisms responsible for the observed sintering dependence on particle size. These results further clarify the relationship between processing parameters and performance and represent important progress toward overcoming fabrication challenges for these materials.
- Published
- 2021
19. Solvent-directed sol-gel assembly of 3-dimensional graphene-tented metal oxides and strong synergistic disparities in lithium storage
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Elizabeth Montalvo, Patrick G. Campbell, Jianchao Ye, Yuanyue Liu, Brand C. Wood, Ich C. Tran, Hanqing Jiang, Yonghao An, Y. Morris Wang, Ming Tang, Marcus A. Worsley, and Juergen Biener
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Materials science ,Nanocomposite ,Renewable Energy, Sustainability and the Environment ,Graphene ,Intercalation (chemistry) ,Oxide ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Pseudocapacitor ,General Materials Science ,Lithium ,0210 nano-technology ,Sol-gel - Abstract
Graphene/metal oxide (GMO) nanocomposites promise a broad range of utilities for lithium ion batteries (LIBs), pseudocapacitors, catalysts, and sensors. When applied as anodes for LIBs, GMOs often exhibit high capacity, improved rate capability and cycling performance. Numerous studies have attributed these favorable properties to a passive role played by the exceptional electronic and mechanical properties of graphene in enabling metal oxides (MOs) to achieve near-theoretical capacities. In contrast, the effects of MOs on the active lithium storage mechanisms of graphene remain enigmatic. Via a unique two-step solvent-directed sol-gel process, we have synthesized and directly compared the electrochemical performance of several representative GMOs, namely Fe2O3/graphene, SnO2/graphene, and TiO2/graphene. We observe that MOs can play an equally important role in empowering graphene to achieve large reversible lithium storage capacity. The magnitude of capacity improvement is found to scale roughly with the surface coverage of MOs, and depend sensitively on the type of MOs. We define a synergistic factor based on the capacity contributions. Our quantitative assessments indicate that the synergistic effect is most achievable in conversion-reaction GMOs (Fe2O3/graphene and SnO2/graphene) but not in intercalation-based TiO2/graphene. However, a long cycle stability up to 2000 cycles was observed in TiO2/graphene nanocomposites. We propose a surface coverage model to qualitatively rationalize the beneficial roles of MOs to graphene. Our first-principles calculations further suggest that the extra lithium storage sites could result from the formation of Li2O at the interface with graphene during the conversion-reaction. These results suggest an effective pathway for reversible lithium storage in graphene and shift design paradigms for graphene-based electrodes.
- Published
- 2016
20. Ideal maximum strengths and defect-induced softening in nanocrystalline-nanotwinned metals
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Jaime Marian, Jianchao Ye, Y. Morris Wang, Alfredo Caro, Zhiliang Pan, Frederic Sansoz, Xing Ke, Ryan T. Ott, Jie Geng, Matthew F. Besser, and Dongxia Qu
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Fabrication ,Materials science ,Mechanical Engineering ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Nanocrystalline material ,0104 chemical sciences ,Mechanics of Materials ,Impurity ,Electrical resistivity and conductivity ,General Materials Science ,Grain boundary ,Composite material ,0210 nano-technology ,Softening ,Nanoscopic scale - Abstract
Strengthening of metals through nanoscale grain boundaries and coherent twin boundaries is manifested by a maximum strength—a phenomenon known as Hall–Petch breakdown. Different softening mechanisms are considered to occur for nanocrystalline and nanotwinned materials. Here, we report nanocrystalline-nanotwinned Ag materials that exhibit two strength transitions dissimilar from the above mechanisms. Atomistic simulations show three distinct strength regions as twin spacing decreases, delineated by positive Hall–Petch strengthening to grain-boundary-dictated (near-zero Hall–Petch slope) mechanisms and to softening (negative Hall–Petch slope) induced by twin-boundary defects. An ideal maximum strength is reached for a range of twin spacings below 7 nm. We synthesized nanocrystalline-nanotwinned Ag with hardness 3.05 GPa—42% higher than the current record, by segregating trace concentrations of Cu impurity (
- Published
- 2018
21. Materials Horizons
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Patrick G. Campbell, Jianchao Ye, Ryan Hensleigh, Eric B. Duoss, James S. Oakdale, Marcus A. Worsley, Christopher M. Spadaccini, Xiaoyu Zheng, Huachen Cui, and Mechanical Engineering
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Materials science ,Graphene ,business.industry ,Process Chemistry and Technology ,Process (computing) ,3D printing ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Mechanics of Materials ,law ,Degradation (geology) ,General Materials Science ,Electrical and Electronic Engineering ,Current (fluid) ,0210 nano-technology ,business - Abstract
3D graphene foams exhibit immense degradation of mechanical properties. Micro-architecture can alleviate this problem, but no current technique meets the manufacturing requirements. Herein we developed a light-based 3D printing process to create hierarchical graphene structures with arbitrary complexity and order-of-magnitude finer features, showing enhanced mechanical properties at decreasing density.
- Published
- 2018
22. Toward digitally controlled catalyst architectures: Hierarchical nanoporous gold via 3D printing
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Jianchao Ye, Christopher M. Spadaccini, Cynthia M. Friend, Cheng Zhu, Wen Chen, Judith Lattimer, Eric B. Duoss, Victor A. Beck, Juergen Biener, Marcus A. Worsley, Zhen Qi, and Mathilde Luneau
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Void (astronomy) ,Materials science ,Materials Science ,Alloy ,3D printing ,Nanotechnology ,02 engineering and technology ,engineering.material ,010402 general chemistry ,01 natural sciences ,Catalysis ,Reaction rate ,Nanoscopic scale ,Research Articles ,Pressure drop ,Multidisciplinary ,business.industry ,Nanoporous ,SciAdv r-articles ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Applied Sciences and Engineering ,engineering ,0210 nano-technology ,business ,Research Article - Abstract
Digitally controlled catalyst architectures via 3D printing potentially revolutionize the design of chemical plants., Monolithic nanoporous metals, derived from dealloying, have a unique bicontinuous solid/void structure that provides both large surface area and high electrical conductivity, making them ideal candidates for various energy applications. However, many of these applications would greatly benefit from the integration of an engineered hierarchical macroporous network structure that increases and directs mass transport. We report on 3D (three-dimensional)–printed hierarchical nanoporous gold (3DP-hnp-Au) with engineered nonrandom macroarchitectures by combining 3D printing and dealloying. The material exhibits three distinct structural length scales ranging from the digitally controlled macroporous network structure (10 to 1000 μm) to the nanoscale pore/ligament morphology (30 to 500 nm) controlled by dealloying. Supercapacitance, pressure drop, and catalysis measurements reveal that the 3D hierarchical nature of our printed nanoporous metals markedly improves mass transport and reaction rates for both liquids and gases. Our approach can be applied to a variety of alloy systems and has the potential to revolutionize the design of (electro-)chemical plants by changing the scaling relations between volume and catalyst surface area.
- Published
- 2018
23. Enhanced electrochemical performance of ion-beam-treated 3D graphene aerogels for lithium ion batteries
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Brandon C. Wood, Jianchao Ye, Yinmin Wang, Supakit Charnvanichborikarn, Marcus A. Worsley, and Sergei O. Kucheyev
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Materials science ,Ion beam ,Chemistry(all) ,Graphene ,chemistry.chemical_element ,Nanotechnology ,General Chemistry ,Electrochemistry ,Anode ,Ion ,law.invention ,symbols.namesake ,chemistry ,Chemical engineering ,law ,symbols ,General Materials Science ,Lithium ,Graphite ,Raman spectroscopy - Abstract
High energy light-ion (3.8 MeV He) bombardment is used to introduce lattice defects in a 3-dimensional (3D) interconnected network of graphene aerogels (GAs). When these materials are used as anodes for lithium ion batteries, we observe improved percentage reversible capacity and cycle stability compared to those without ion-beam treatment. Furthermore, all ion-beam treated 3D graphene samples exhibit substantially higher Coulombic efficiencies, suggesting at beneficial role of vacancy-type defects in stabilizing solid-electrolyte interphases. Although 3D graphene exhibits initial reversible capacities that are 2–3 times higher than that of graphite (∼372 mAh/g), fast capacity fading is observed but becomes more stable after ion-beam treatment. Our experimental results demonstrate that ion-beam treatment is an effective route to tune and produce good-performance graphene electrodes, and that vacancy-type defects help to promote reversible lithium storage capacity in graphene. We further observe that 3D GAs irradiated to the highest dose studied (10 16 cm −2 ) fail rapidly upon electrochemical cycling, likely caused by the excessive ion-beam damage and graphene restacking. Raman I (D)/ I (D′) signature is considered linked to defect type in graphene and thus is proposed, for the first time, as an indicator of the reversible capacity for GAs.
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- 2015
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24. Mitigating mechanical failure of crystalline silicon electrodes for lithium batteries by morphological design
- Author
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Jianchao Ye, Yet-Ming Chiang, Yonghao An, Brandon C. Wood, Ming Tang, Hanqing Jiang, Y. Morris Wang, Massachusetts Institute of Technology. Department of Materials Science and Engineering, An, Yonghao, and Chiang, Yet-Ming
- Subjects
Materials science ,Alloy ,General Physics and Astronomy ,chemistry.chemical_element ,Nanotechnology ,engineering.material ,Amorphous solid ,Anode ,chemistry ,Electrode ,engineering ,Lithium ,Crystalline silicon ,Physical and Theoretical Chemistry ,Composite material ,Severe plastic deformation ,Anisotropy - Abstract
Although crystalline silicon (c-Si) anodes promise very high energy densities in Li-ion batteries, their practical use is complicated by amorphization, large volume expansion and severe plastic deformation upon lithium insertion. Recent experiments have revealed the existence of a sharp interface between crystalline Si (c-Si) and the amorphous Li[subscript x]Si alloy during lithiation, which propagates with a velocity that is orientation dependent; the resulting anisotropic swelling generates substantial strain concentrations that initiate cracks even in nanostructured Si. Here we describe a novel strategy to mitigate lithiation-induced fracture by using pristine c-Si structures with engineered anisometric morphologies that are deliberately designed to counteract the anisotropy in the crystalline/amorphous interface velocity. This produces a much more uniform volume expansion, significantly reducing strain concentration. Based on a new, validated methodology that improves previous models of aniso tropic swelling of c-Si, we propose optimal morphological designs for c-Si pillars and particles. The advantages of the new morphologies are clearly demonstrated by mesoscale simulations and verified by experiments on engineered c-Si micropillars. The results of this study illustrate that morphological design is effective in improving the fracture resistance of micron-sized Si electrodes, which will facilitate their practical application in next-generation Li-ion batteries. The model and design approach present in this paper also have general implications for the study and mitigation of mechanical failure of electrode materials that undergo large anisotropic volume change upon ion insertion and extraction., United States. Department of Energy (DE - SC0002626)
- Published
- 2015
25. Structural Optimization of 3D Porous Electrodes for High-Rate Performance Lithium Ion Batteries
- Author
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Y. Morris Wang, Monika M. Biener, Jianchao Ye, Juergen Biener, and Andreas C. Baumgaertel
- Subjects
Length scale ,Materials science ,business.industry ,Nanoporous ,General Engineering ,General Physics and Astronomy ,chemistry.chemical_element ,Nanotechnology ,Electrolyte ,Current collector ,Electrochemistry ,Atomic layer deposition ,chemistry ,Electrode ,Optoelectronics ,General Materials Science ,Lithium ,business - Abstract
Much progress has recently been made in the development of active materials, electrode morphologies and electrolytes for lithium ion batteries. Well-defined studies on size effects of the three-dimensional (3D) electrode architecture, however, remain to be rare due to the lack of suitable material platforms where the critical length scales (such as pore size and thickness of the active material) can be freely and deterministically adjusted over a wide range without affecting the overall 3D morphology of the electrode. Here, we report on a systematic study on length scale effects on the electrochemical performance of model 3D np-Au/TiO2 core/shell electrodes. Bulk nanoporous gold provides deterministic control over the pore size and is used as a monolithic metallic scaffold and current collector. Extremely uniform and conformal TiO2 films of controlled thickness were deposited on the current collector by employing atomic layer deposition (ALD). Our experiments demonstrate profound performance improvements by matching the Li(+) diffusivity in the electrolyte and the solid state through adjusting pore size and thickness of the active coating which, for 200 μm thick porous electrodes, requires the presence of 100 nm pores. Decreasing the thickness of the TiO2 coating generally improves the power performance of the electrode by reducing the Li(+) diffusion pathway, enhancing the Li(+) solid solubility, and minimizing the voltage drop across the electrode/electrolyte interface. With the use of the optimized electrode morphology, supercapacitor-like power performance with lithium-ion-battery energy densities was realized. Our results provide the much-needed fundamental insight for the rational design of the 3D architecture of lithium ion battery electrodes with improved power performance.
- Published
- 2014
26. Porous Materials: Direct Laser Writing of Low-Density Interdigitated Foams for Plasma Drive Shaping (Adv. Funct. Mater. 43/2017)
- Author
-
Leonardus Bimo Bayu Aji, Theodore F. Baumann, Raymond F. Smith, Jean-Baptiste Forien, Peter Amendt, James S. Oakdale, Trevor M. Willey, Suzanne Ali, William L. Smith, Anthony van Buuren, Juergen Biener, Matthew A. Worthington, Hye-Sook Park, Shon Prisbrey, and Jianchao Ye
- Subjects
Biomaterials ,Materials science ,High energy density physics ,law ,Electrochemistry ,Low density ,Nanotechnology ,Plasma ,Condensed Matter Physics ,Porous medium ,Laser ,Electronic, Optical and Magnetic Materials ,law.invention - Published
- 2017
27. Addendum: Multiscale metallic metamaterials
- Author
-
Nicholas X. Fang, Christopher M. Spadaccini, Nicholas Rodriguez, Da Chen, Todd H. Weisgraber, Julie A. Jackson, William L. Smith, Jianchao Ye, Xiaoyu Zheng, Huachen Cui, and Bryan D. Moran
- Subjects
Mechanical Engineering ,Metamaterial ,Addendum ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Mechanics of Materials ,General Materials Science ,0210 nano-technology - Published
- 2017
28. Mechanical Switching of Nanoscale Multiferroic Phase Boundaries
- Author
-
Ce-Wen Nan, Yongjun Li, Xiaobing Ren, Jianchao Ye, Chuan Shou Wang, Jinxing Zhang, Jianjun Wang, Fei Xue, Renci Peng, Gaoyang Gou, Yong Yang, Yan Wei, Long Qing Chen, Jing Wang, Xuliang Deng, and Xiaoxing Ke
- Subjects
Condensed Matter - Materials Science ,Materials science ,Condensed matter physics ,Sensing applications ,Physics ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Condensed Matter Physics ,Piezoelectricity ,Ferroelectricity ,Potential energy ,Piezomagnetism ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Chemistry ,Condensed Matter::Materials Science ,Lattice (order) ,Electrochemistry ,Multiferroics ,Engineering sciences. Technology ,Nanoscopic scale - Abstract
Tuning the lattice degree of freedom in nanoscale functional crystals is critical to exploit the emerging functionalities such as piezoelectricity, shape-memory effect, or piezomagnetism, which are attributed to the intrinsic lattice-polar or lattice-spin coupling. Here it is reported that a mechanical probe can be a dynamic tool to switch the ferroic orders at the nanoscale multiferroic phase boundaries in BiFeO3 with a phase mixture, where the material can be reversibly transformed between the soft tetragonal-like and the hard rhombohedral-like structures. The microscopic origin of the nonvolatile mechanical switching of the multiferroic phase boundaries, coupled with a reversible 180 degrees rotation of the in-plane ferroelectric polarization, is the nanoscale pressure-induced elastic deformation and reconstruction of the spontaneous strain gradient across the multiferroic phase boundaries. The reversible control of the room-temperature multiple ferroic orders using a pure mechanical stimulus may bring us a new pathway to achieve the potential energy conversion and sensing applications.
- Published
- 2017
- Full Text
- View/download PDF
29. Quantitative Phase Composition of TiO2-Coated Nanoporous Au Monoliths by X-ray Absorption Spectroscopy and Correlations to Catalytic Behavior
- Author
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Tony van Buuren, Jianchao Ye, Arne Wittstock, Joshua D. Kuntz, Jonathan R. I. Lee, Andre Wichmann, Monika M. Biener, Michael Bagge-Hansen, Trevor M. Willey, Marcus Bäumer, and Juergen Biener
- Subjects
X-ray absorption spectroscopy ,Materials science ,Nanoporous ,Annealing (metallurgy) ,Nanotechnology ,XANES ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Catalysis ,Amorphous solid ,Atomic layer deposition ,General Energy ,Chemical engineering ,Physical and Theoretical Chemistry ,Spectroscopy - Abstract
Porous titania/metal composite materials have many potential applications in the fields of green catalysis, energy harvesting, and storage in which both the overall morphology of the nanoporous host material and the crystallographic phase of the titania (TiO2) guest determine the material’s performance. New insights into the structure–function relationships of these materials were obtained by near-edge X-ray absorption fine structure (NEXAFS) spectroscopy that, for example, provides quantitative crystallographic phase composition from ultrathin, nanostructured titania films, including sensitivity to amorphous components. Here, we demonstrate that crystallographic phase, morphology, and catalytic activity of TiO2-functionalized nanoporous gold (np-Au) can be controlled by a simple annealing procedure (T < 1300 K). The material was prepared by atomic layer deposition of ∼2 nm thick TiO2 on millimeter-sized samples of np-Au (40–50 nm mean ligament size) and catalytically investigated with respect to aerobic ...
- Published
- 2014
30. Enhanced lithiation and fracture behavior of silicon mesoscale pillars via atomic layer coatings and geometry design
- Author
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Jianchao Ye, Ming Tang, Yonghao An, R. J. Nikolic, Hanqing Jiang, Tae Wook Heo, Monika M. Biener, and Y. M. Wang
- Subjects
Nanostructure ,Materials science ,Silicon ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Geometry ,Electrolyte ,Nanowire battery ,Lithium-ion battery ,law.invention ,Atomic layer deposition ,chemistry ,law ,Electrode ,Crystalline silicon ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry - Abstract
Crystalline silicon nanostructures are commonly known to exhibit anisotropic expansion behavior during the lithiation that leads to grooving and fracture. Here we report surprisingly relatively uniform volume expansion behavior of large aspect-ratio (∼25), well-patterned, n-type (100) silicon micropillars (∼2 μm diameter) during the initial lithiation. The comparison results with and without atomic layer metal oxides (Al 2 O 3 and TiO 2 ) coatings reveal drastically enhanced solid electrolyte interphase (SEI) formation, higher volume expansion, and increased anisotropy. Square-pillars are found to exhibit nearly twice volume expansion without fracture compared to circular-pillars. Models are invoked to qualitatively address these beneficial or detrimental properties of silicon for lithium ion battery. Our experiments and computer simulations point at the critical relevance of SEI and pristine geometry in regulating volume expansion and failure. ALD-coated ultrathin metal oxides can act as an ion channel gate that helps promote fast Li + transport into the bulk by changing the surface kinetics, suggesting new ways of designing electrodes for high-performance lithium ion battery applications.
- Published
- 2014
31. Energy Coupling Mechanisms and Scaling Behavior Associated with Laser Powder Bed Fusion Additive Manufacturing
- Author
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Gabe Guss, Manyalibo J. Matthews, Saad A. Khairallah, Jianchao Ye, James Belak, Michael F. Crumb, and Alexander M. Rubenchik
- Subjects
Fusion ,Materials science ,law ,Powder bed ,Laser beam welding ,General Materials Science ,Energy coupling ,Composite material ,Condensed Matter Physics ,Thermal analysis ,Laser ,Scaling ,law.invention - Published
- 2019
32. Grain size dependent physical and chemical properties of thick CVD diamond films for high energy density physics experiments
- Author
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Jianchao Ye, T. Braun, S. J. Shin, Lutz Kirste, Anthony van Buuren, Nick Teslich, E. Woerner, Claus-C. Roehlig, Christoph Dawedeit, Sergei O. Kucheyev, Marco Wolfer, Y. Morris Wang, Bassem S. El-Dasher, Monika M. Biener, Michael Bagge-Hansen, Christoph Wild, Trevor M. Willey, Juergen Biener, and Alex V. Hamza
- Subjects
Materials science ,Synthetic diamond ,Mechanical Engineering ,Material properties of diamond ,Mineralogy ,chemistry.chemical_element ,Diamond ,General Chemistry ,Chemical vapor deposition ,engineering.material ,Grain size ,Electronic, Optical and Magnetic Materials ,law.invention ,chemistry ,law ,Plasma-enhanced chemical vapor deposition ,Materials Chemistry ,engineering ,Surface roughness ,Electrical and Electronic Engineering ,Composite material ,Carbon - Abstract
We report on the grain size dependent morphological, physical and chemical properties of thick microwave-plasma assisted chemical vapor deposited (MPCVD) diamond films that are used as target materials for high energy density physics experiments at the Lawrence Livermore National Laboratory. Control over the grain size, ranging from several μm to a few nm, was achieved by adjusting the CH4 content of the CH4/H2 feed gas. The effect of grain size on surface roughness, morphology, texture, density, hydrogen and graphitic carbon content was systematically studied by a variety of techniques. For depositions performed at 35 to 45 mbar and 3000 W microwave power (power density ~ 10 W cm− 3), an abrupt transition from micro-crystalline diamond to nanocrystalline diamond was observed at 3% CH4. This transition is accompanied by a dramatic decrease in surface roughness, a six percent drop in density and an increasing content in hydrogen and graphitic carbon impurities. Guided by these results, layered nano-microhybrid diamond samples were prepared by periodically changing the growth conditions from nano- to microcrystalline.
- Published
- 2013
33. Dual character of stable shear banding in bulk metallic glasses
- Author
-
Yong Yang, Jianchao Ye, C.T. Liu, and Jian Lu
- Subjects
Materials science ,Amorphous metal ,Mechanical Engineering ,Alloy ,Metals and Alloys ,Energy balance ,Mineralogy ,General Chemistry ,engineering.material ,Dissipation ,Plastic energy ,Shear (geology) ,Mechanics of Materials ,Sample size determination ,Materials Chemistry ,engineering ,Composite material ,Softening - Abstract
In this work, a systematical study of the stable shear banding behavior is performed across a wide range of alloy compositions of bulk metallic glasses (BMGs). Through microcompression, it can be demonstrated that the stable shear banding behavior could exhibit a dual character of stochastic and deterministic propagations. Different from the stochastic character, which is found insensitive to sample sizes, the deterministic character displays a clear trend of a sample size effect, which can be captured by the energy balance principle. Based on the theoretical framework laid out in this work, a correlation between the plastic energy dissipation and the sample size effect is established, which can be then utilized to explore the influence of the alloy’s chemical compositions on the behavior of shear-induced material softening. Finally, the energy-based formalisms aimed to quantify the shear banding size effect in MGs are discussed.
- Published
- 2011
34. Compressible Electrodes: 3D-Printed, Superelastic Polypyrrole-Graphene Electrodes with Ultrahigh Areal Capacitance for Electrochemical Energy Storage (Adv. Mater. Technol. 7/2018)
- Author
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Jianchao Ye, Wen Chen, Christopher M. Spadaccini, Eric B. Duoss, Cheng Zhu, Juergen Biener, Zhen Qi, and Marcus A. Worsley
- Subjects
010302 applied physics ,3d printed ,Materials science ,business.industry ,Areal capacitance ,3D printing ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Polypyrrole ,01 natural sciences ,Industrial and Manufacturing Engineering ,chemistry.chemical_compound ,chemistry ,Graphene electrode ,Mechanics of Materials ,0103 physical sciences ,Electrode ,Compressibility ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business ,Electrochemical energy storage - Published
- 2018
35. 3D‐Printed, Superelastic Polypyrrole–Graphene Electrodes with Ultrahigh Areal Capacitance for Electrochemical Energy Storage
- Author
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Marcus A. Worsley, Christopher M. Spadaccini, Eric B. Duoss, Cheng Zhu, Juergen Biener, Jianchao Ye, Zhen Qi, and Wen Chen
- Subjects
3d printed ,Materials science ,business.industry ,Areal capacitance ,3D printing ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Polypyrrole ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,chemistry.chemical_compound ,Graphene electrode ,chemistry ,Mechanics of Materials ,General Materials Science ,0210 nano-technology ,business ,Electrochemical energy storage - Published
- 2018
36. Extraction of bulk metallic-glass yield strengths using tapered micropillars in micro-compression experiments
- Author
-
Jianchao Ye, Peter K. Liaw, Jian Lu, and Yong Yang
- Subjects
Materials science ,Yield (engineering) ,Amorphous metal ,Mechanics of Materials ,Mechanical Engineering ,Extraction (chemistry) ,Materials Chemistry ,Metals and Alloys ,Forensic engineering ,General Chemistry ,Nanoindentation ,Composite material ,Compression (physics) - Abstract
In this paper, a formula is derived based on the Mohr–Coulomb law to extract the bulk metallic-glass (BMG) yield strengths in the micro-compression experiments, accounting for the effects of a variety of geometrical parameters arising from the tapered micropillar geometries. The experimental results on three classes of BMGs, comprising the Zr-, Mg- and Fe-based BMGs, show that the yield strengths of the BMG micropillars exhibit a very weak size effect as compared with the literature data obtained from the micro-crystals. The validity of the derived formula is then checked through the comparison with the measurements from the nanoindentation and macro-compression experiments.
- Published
- 2010
37. Metallic glasses: Gaining plasticity for microsystems
- Author
-
Jianchao Ye, Yanfei Gao, Yong Yang, Jian Lu, and Peter K. Liaw
- Subjects
Materials science ,Amorphous metal ,Microsystem ,General Engineering ,Formability ,General Materials Science ,Nanotechnology ,Plasticity ,Composite material ,Ductility - Abstract
Since the 1960s, metallic glasses (MGs) have attracted tremendous re-search interest in materials science and engineering, given their unique cornbination of mechanical properties. How-ever, the industrial applications of MGs have been hindered due to their lack of ductility in bulk form at room temperature. In contrast, it was observed that MGs could exhibit excellent plasticity at the small size scale. In this article, we summarize the related experimental findings having been reported so far together with the possible origins of such a size effect in MGs. The enhanced plasticity of MGs in small volumes, together with their high mechanical strengths and remarkable thermoplastic formability, strongly implies that MGs are the promising materials for fabricating the next generation of micro- and nano-devices.
- Published
- 2010
38. Study of the intrinsic ductile to brittle transition mechanism of metallic glasses
- Author
-
Jianchao Ye, Peter K. Liaw, Jian Lu, and Yong Yang
- Subjects
Amorphous metal ,Materials science ,Polymers and Plastics ,Kinetics ,Metals and Alloys ,Elastic energy ,Electronic, Optical and Magnetic Materials ,Physics::Fluid Dynamics ,Condensed Matter::Soft Condensed Matter ,Brittleness ,Shear (geology) ,Ceramics and Composites ,Forensic engineering ,Compression test ,Composite material ,Shear band ,Softening - Abstract
We provide a quantitative account of the shear-banding behavior in Mg-based bulk metallic glasses. Microcompression experiments showed that shear bands propagated in an intermittent manner at the micron and submicron scales. The shear-banding kinetics involves competition between shear-induced softening and subsequent recovery mechanisms; the former depends strongly on the elastic energy release rate at the onset of shear-banding, whereas the latter is correlated with the shear-band offset and scales with the characteristic dimension of the microsamples. With the increase in the sample size, more elastic energy is released into the shear band, which results in larger fluctuations in the serrated plastic flows and the propensity for unstable shear-band propagation. The outcome of the current study reveals the origin of the intrinsic ductile to brittle transition mechanism in metallic glasses.
- Published
- 2009
39. Effects of specimen geometry and base material on the mechanical behavior of focused-ion-beam-fabricated metallic-glass micropillars
- Author
-
Jianchao Ye, Peter K. Liaw, Jian Lu, Yong Yang, and F.X. Liu
- Subjects
Amorphous metal ,Materials science ,Polymers and Plastics ,Metals and Alloys ,Pillar ,Base (geometry) ,Modulus ,Geometry ,Material system ,Nanoindentation ,Focused ion beam ,Electronic, Optical and Magnetic Materials ,Characterization (materials science) ,Ceramics and Composites - Abstract
An investigation of the focused-ion-beam-based microcompression experiments was conducted using metallic-glass micropillars. The results displayed an apparent geometry dependence of the measured pillar’s Young’s modulus if the formula in the literature was used for the analysis of the experimental data. However, if the effects of the base material and pillar geometry were taken into account with the aid of finite-element simulations, it was shown that the microcompression experiments can reach a resolution similar to that of the nanoindentation tests in the measurement of the material’s mechanical properties, and therefore provide an alternative to the nanoindentation experiment in applications that require the characterization of local mechanical properties in multi-structured/multi-phased material systems.
- Published
- 2009
40. Universal roles of hydrogen in electrochemical performance of graphene: high rate capacity and atomistic origins
- Author
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Patrick G. Campbell, Yuanyue Liu, S. J. Shin, Jianchao Ye, Tae Wook Heo, Marcus A. Worsley, Jonathan R. I. Lee, Brandon C. Wood, Mitchell T. Ong, Michael Bagge-Hansen, Manyalibo J. Matthews, Y. Morris Wang, and Supakit Charnvanichborikarn
- Subjects
Multidisciplinary ,Materials science ,Hydrogen ,Graphene ,Kinetics ,chemistry.chemical_element ,Nanotechnology ,Bioinformatics ,Electrochemistry ,Pseudocapacitance ,Article ,Ion ,law.invention ,chemistry ,Affordable and Clean Energy ,law ,Electrode ,Nanofoam - Abstract
Atomic hydrogen exists ubiquitously in graphene materials made by chemical methods. Yet determining the effect of hydrogen on the electrochemical performance of graphene remains a significant challenge. Here we report the experimental observations of high rate capacity in hydrogen-treated 3-dimensional (3D) graphene nanofoam electrodes for lithium ion batteries. Structural and electronic characterization suggests that defect sites and hydrogen play synergistic roles in disrupting sp2 graphene to facilitate fast lithium transport and reversible surface binding, as evidenced by the fast charge-transfer kinetics and increased capacitive contribution in hydrogen-treated 3D graphene. In concert with experiments, multiscale calculations reveal that defect complexes in graphene are prerequisite for low-temperature hydrogenation and that the hydrogenation of defective or functionalized sites at strained domain boundaries plays a beneficial role in improving rate capacity by opening gaps to facilitate easier Li penetration. Additional reversible capacity is provided by enhanced lithium binding near hydrogen-terminated edge sites. These findings provide qualitative insights in helping the design of graphene-based materials for high-power electrodes.
- Published
- 2015
41. Direct Laser Writing of Low‐Density Interdigitated Foams for Plasma Drive Shaping
- Author
-
Leonardus Bimo Bayu Aji, Jean-Baptiste Forien, Raymond F. Smith, Hye-Sook Park, Suzanne Ali, Theodore F. Baumann, William L. Smith, Anthony van Buuren, Matthew A. Worthington, Jianchao Ye, Shon Prisbrey, Peter Amendt, Juergen Biener, Trevor M. Willey, and James S. Oakdale
- Subjects
Materials science ,Fabrication ,business.industry ,Analytical chemistry ,02 engineering and technology ,Plasma ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Laser ,01 natural sciences ,Energy storage ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,law.invention ,Biomaterials ,Image stitching ,law ,Electrochemistry ,Optoelectronics ,0210 nano-technology ,business ,Porous medium ,Porosity ,Order of magnitude - Abstract
Monolithic porous bulk materials have many promising applications ranging from energy storage and catalysis to high energy density physics. High resolution additive manufacturing techniques, such as direct laser writing via two photon polymerization (DLW-TPP), now enable the fabrication of highly porous microlattices with deterministic morphology control. In this work, DLW-TPP is used to print millimeter-sized foam reservoirs (down to 0.06 g cm−3) with tailored density-gradient profiles, where density is varied by over an order of magnitude (for instance from 0.6 to 0.06 g cm−3) along a length of
- Published
- 2017
42. Post-print UV curing method for improving the mechanical properties of prototypes derived from two-photon lithography
- Author
-
Jianchao Ye, James S. Oakdale, William L. Smith, and Juergen Biener
- Subjects
Rapid prototyping ,Materials science ,business.industry ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Multiphoton lithography ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Photon counting ,0104 chemical sciences ,Optics ,Polymerization ,visual_art ,Ultimate tensile strength ,visual_art.visual_art_medium ,UV curing ,Composite material ,0210 nano-technology ,business ,Acrylic resin ,Curing (chemistry) - Abstract
Two photon polymerization (TPP) is a precise, reliable, and increasingly popular technique for rapid prototyping of micro-scale parts with sub-micron resolution. The materials of choice underlying this process are predominately acrylic resins cross-linked via free-radical polymerization. Due to the nature of the printing process, the derived parts are only partially cured and the corresponding mechanical properties, i.e. modulus and ultimate strength, are lower than if the material were cross-linked to the maximum extent. Herein, post-print curing via UV-driven radical generation, is demonstrated to increase the overall degree of cross-linking of low density, TPP-derived structures.
- Published
- 2016
43. Corrigendum to 'Enhanced lithiation and fracture behavior of silicon mesoscale pillars via atomic layer coatings and geometry design' J. Power Sources 248 (2014) 447–456]
- Author
-
Monika M. Biener, Ming Tang, Yonghao An, R. J. Nikolic, Y. M. Wang, Hanqing Jiang, Tae Wook Heo, and Jianchao Ye
- Subjects
Materials science ,Silicon ,Renewable Energy, Sustainability and the Environment ,Mesoscale meteorology ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Nanotechnology ,Power (physics) ,chemistry ,Fracture (geology) ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Composite material ,Layer (electronics) - Published
- 2015
44. Bulk Materials: Ultra-strong and Low-Density Nanotubular Bulk Materials with Tunable Feature Sizes (Adv. Mater. 28/2014)
- Author
-
Jianchao Ye, Alex V. Hamza, Juergen Biener, S. J. Shin, Monika M. Biener, Y. Morris Wang, and Theodore F. Baumann
- Subjects
Materials science ,Mechanics of Materials ,Feature (computer vision) ,Mechanical Engineering ,Low density ,General Materials Science ,Nanotechnology ,Thin film ,Porous medium ,Nanomaterials - Published
- 2014
45. Metallic glasses: Gaining plasticity for microsystems.
- Author
-
Yong Yang, Jianchao Ye, Jian Lu, Yanfei Gao, and Liaw, Peter K.
- Subjects
AMORPHOUS substances ,METALLIC glasses ,MATERIAL plasticity ,RHEOLOGY ,MATERIALS science ,PHYSICAL sciences - Abstract
Since the 1960s, metallic glasses (MGs) have attracted tremendous re-search interest in materials science and engineering, given their unique cornbination of mechanical properties. How-ever, the industrial applications of MGs have been hindered due to their lack of ductility in bulk form at room temperature. In contrast, it was observed that MGs could exhibit excellent plasticity at the small size scale. In this article, we summarize the related experimental findings having been reported so far together with the possible origins of such a size effect in MGs. The enhanced plasticity of MGs in small volumes, together with their high mechanical strengths and remarkable thermoplastic formability, strongly implies that MGs are the promising materials for fabricating the next generation of micro- and nano-devices. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
46. Determining processing behaviour of pure Cu in laser powder bed fusion using direct micro-calorimetry
- Author
-
Leonidas Gargalis, James W. Murray, Adam T. Clare, Ian Ashcroft, Jianchao Ye, Richard J.M. Hague, Manyalibo J. Matthews, Maria Strantza, and Alexander M. Rubenchik
- Subjects
0209 industrial biotechnology ,Materials science ,Far-infrared laser ,Metals and Alloys ,02 engineering and technology ,Molar absorptivity ,Laser ,Industrial and Manufacturing Engineering ,Computer Science Applications ,law.invention ,020303 mechanical engineering & transports ,020901 industrial engineering & automation ,Thermal conductivity ,0203 mechanical engineering ,law ,Modeling and Simulation ,Boiling ,Ceramics and Composites ,Deposition (phase transition) ,Laser power scaling ,Composite material ,Keyhole - Abstract
Copper is challenging to process by laser powder bed fusion (LPBF) given its high reflectivity at common infrared laser diode wavelengths and high thermal conductivity. Successful deposition of copper in a predictable and repeatable fashion relies on understanding the development of the keyhole melting regime, as well as heating, melting, boiling and vapour formation behaviour when interacting with a laser beam within an LPBF environment. In this study, in situ optical absorptivity measurements are used to clarify the complex physics of the laser material interaction. Absorptivity of laser energy is measured using direct micro-calorimetry and compared to melt pool depth in correlation to processing parameters. The measured absorptivity for a 100 μm layer thickness of powder was found to be approximately four times higher than that of the bare polished discs. It was also shown that high laser power above 500 W and scan speed up to 150 mm/s are appropriate for effective melting of the powder layer, with these parameters overcoming the threshold required to achieve keyhole melting. This is explained by multiple reflections withing the powder particles and the lower thermal conductivity of packed powder in comparison to bare discs. Melt pool formation was found to be highly unstable and an explosive behavior was observed when in the keyhole regime, caused by high fluctuations in absorptivity values. This work demonstrates calorimetry can be used to monitor melting behaviour in a real-time fashion during processing for this challenging to proces material, thereby avoiding unnecessary parametric optimisation. In addition, the parametric window for optimum processing revealed here can inform future work.
- Full Text
- View/download PDF
47. Toward digitally controlled catalyst architectures: Hierarchical nanoporous gold via 3D printing.
- Author
-
Cheng Zhu, Zhen Qi, Beck, Victor A., Luneau, Mathilde, Lattimer, Judith, Wen Chen, Worsley, Marcus A., Jianchao Ye, Duoss, Eric B., Spadaccini, Christopher M., Friend, Cynthia M., and Biener, Juergen
- Subjects
- *
NANOPOROUS materials , *POROSITY , *ALLOYS , *CATALYSTS , *ELECTROCHEMISTRY - Abstract
The article focuses on a study which reports on report on 3D printed hierarchical nanoporous gold (3DP-hnp-Au) with engineered nonrandom macroarchitectures by combining 3D printing and dealloying. It mentions that thermal decomposition of polymeric binder creates microscale porosity within the printed features. It states that variety of alloy systems has potential to revolutionize design of electrochemical plants by changing scaling relations between volume and catalyst surface area.
- Published
- 2018
- Full Text
- View/download PDF
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