Large-scale nanoshaping of ultrasmooth 3D crystalline metallic structures

Huang, Gao; Hu, Yijun; Xuan, Yi; Li, Ji; Yang, Yongying; Martínez, Ramsés V.; Li, Chunyu; Luo, Jian; Qi, Minghao; Cheng, Gary J.

doi:10.1126/science.1260139

Cited by 177 publications

(135 citation statements)

References 52 publications

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“…For friction welding, the low efficiency and welding defects are concerning. Alternatively, highpower-density laser has attracted enormous research interest and found its wide application in a broad branch of manufacturing areas including selective laser sintering and three-dimensional printing [1][2][3][4][5][6], surface nanostructuring [7][8][9][10][11][12], multimaterial joining and integration [13][14][15][16][17], material removal [18,19], and mechanical/optical property enhancements [20][21][22][23]. Characteristics, such as contact-free processing, good flexibility and tunablity, high efficiency, and throughput, make laser a feasible route for welding of 42CrMo [24,25].…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical study on laser keyhole welding of 42CrMo under air and argon atmosphere

et al. 2016

Int J Adv Manuf Technol

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Laser keyhole welding of 42CrMo in air and argon atmospheres has been studied both experimentally and numerically. Significant macroscale difference is observed for welding carried out under argon and air shielding. Fusion zone of welding under argon shielding has a "▽" shape, while it has a "U" shape for welding in air. The surface of the weldment is smoother for welding in argon when compared with that in air. Oxygen effect is proposed to account for the experimental results. A three-dimensional heat transfer model with a predefined keyhole is developed to study the heat transport and fluid flow in laser welding process. The variation of weld pool geometry and temperature history is investigated for different oxygen concentrations. It is found that a small amount of oxygen could significantly modify the weld pool dimension, while keeping the temperature history of materials, and thus the microstructure, in the fusion zone and heat-affected zone unchanged.

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Section: Introductionmentioning

confidence: 99%

Experimental and numerical study on laser keyhole welding of 42CrMo under air and argon atmosphere

et al. 2016

Int J Adv Manuf Technol

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“…These methods allow the fabrication of homogeneously metallic nanopatterns but are costly, owing to time-consuming, multistep processes, and are also limited in preparing nanostructures with low-aspect ratios27. At present, rapid fabrication of metallic nanostructures in terms of controllability (for example, resolution, precision and uniformity), material diversity, cost and especially high-aspect ratio remains a significant challenge2829.…”

mentioning

confidence: 99%

“…Recently, Schroers and co-workers333435 succeed in nanomoulding bulk metallic glasses (BMGs) above their glass transition temperatures ( T g ) and below crystallization temperatures ( T x ), which has triggered broad research in exploring BMGs' applications such as electrochemical catalysts36 and micro/nano-electro-mechanical systems3738. However, a similar process has been considered infeasible for nanoimprinting crystalline metals below their melting temperatures ( T m )283337 because of the limitations on formability originating from size effect in plasticity439 and grain size effect3740. There has been a few attempts using templates to nanoimprint metals close to forging41, but the temperature is too low and the embossed smallest feature size is usually on the order of grain sizes.…”

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confidence: 99%

One-step fabrication of crystalline metal nanostructures by direct nanoimprinting below melting temperatures

Liu

2017

Nat Commun

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Controlled fabrication of metallic nanostructures plays a central role in much of modern science and technology, because changing the dimensions of a nanocrystal enables tailoring of its mechanical, electronic, optical, catalytic and antibacterial properties. Here we show direct superplastic nanoimprinting (SPNI) of crystalline metals well below their melting temperatures, generating ordered nanowire arrays with aspect ratios up to ∼2,000 and imprinting features as small as 8 nm. Surface-enhanced Raman scattering (SERS) spectra reveal strongly enhanced electromagnetic signals from the prepared nanorod arrays with sizes up to ∼100 nm, which indicates that our technique can provide an ideal way to fabricate robust SERS substrates. SPNI, as a one-step, controlled and reproducible nanofabrication method, could facilitate the applications of metal nanostructures in bio-sensing, diagnostic imaging, catalysis, food industry and environmental conservation.

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“…Existing methods to fabricate nanostructured metallic surfaces possess considerable limitations. For example, laser treatment 12,13 , shock forming 14 , and thermoplastic forming against anodized aluminum oxide (AAO) 6 exhibit difficulties with producing complex, non-planar geometries. There are also limitations on the final surface composition and crystal structure, such as those present with electrochemical dealloying [15][16][17] .…”

Section: Introductionmentioning

confidence: 99%

Multiscale patterning of a metallic glass using sacrificial imprint lithography

et al. 2015

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Bulk metallic glasses (BMGs) have been developed as a means to achieve durable multiscale, nanotextured surfaces with desirable properties dictated by topography for a multitude of applications. One barrier to this achievement is the lack of a bridging technique between macroscale thermoplastic forming and nanoimprint lithography, which arises from the difficulty and cost of generating controlled nanostructures on complex geometries using conventional top-down approaches. This difficulty is compounded by the necessary destruction of any resulting reentrant structures during rigid demolding. We have developed a generalized method to overcome this limitation by sacrificial template imprinting using zinc oxide (ZnO) nanostructures. It is established that such structures can be grown inexpensively and quickly with tunable morphologies on a wide variety of substrates out of solution, which we exploit to generate the nanoscale portion of the multiscale pattern through this bottom-up approach. In this way, we achieve metallic structures that simultaneously demonstrate features from the macroscale down to the nanoscale, requiring only the top-down fabrication of macro/microstructured molds. Upon detachment of the formed part from the multiscale molds, the ZnO remains embedded in the surface and can be removed by etching in mild conditions to both regenerate the mold and render the surface of the BMGs nanoporous. The ability to pattern metallic surfaces in a single step on length scales from centimeters down to nanometers is a critical step toward fabricating devices with complex shapes that rely on multiscale topography for their intended functions, such as biomedical and electrochemical applications.

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Large-scale nanoshaping of ultrasmooth 3D crystalline metallic structures

Cited by 177 publications

References 52 publications

Experimental and numerical study on laser keyhole welding of 42CrMo under air and argon atmosphere

Experimental and numerical study on laser keyhole welding of 42CrMo under air and argon atmosphere

One-step fabrication of crystalline metal nanostructures by direct nanoimprinting below melting temperatures

Multiscale patterning of a metallic glass using sacrificial imprint lithography

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