In the development of microfluidic chips, conventional 2D processing technologies contribute to the manufacturing of basic microchannel networks. Nevertheless, in the pursuit of versatile ...microfluidic chips, flexible integration of multifunctional components within a tiny chip is still challenging because a chip containing micro‐channels is a non‐flat substrate. Recently, on‐chip laser processing (OCLP) technology has emerged as an appealing alternative to achieve chip functionalization through in situ fabrication of 3D microstructures. Here, the recent development of OCLP‐enabled multifunctional microfluidic chips, including several accessible photochemical/photophysical schemes, and photosensitive materials permiting OCLP, is reviewed. To demonstrate the capability of OCLP technology, a series of typical micro‐components fabricated using OCLP are introduced. The prospects and current challenges of this field are discussed.
In this review, recent developments of on‐chip laser‐processing‐enabled multifuctional microflidic chips are summarized. Several accessible photochemical/photophysical schemes and photosensitive materials, as well as a series of typical functional chip components, have been reviewed. The future prospects and current challenges in this field have been discussed.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The Companion Paper Zaengle T, Gibson UJ, Hawkins TW, McMillen C, Ballato J. Comprehensive phase analysis of GaAs:(Cu, Au) systems in molten core fibers. Opt Mater (Amst). 2024;150(March):115256. ...doi:10.1016/j.optmat.2024.115256 presents the thermochemical analysis of the GaAs:Cu and GaAs:Au phases in flux-assisted molten core fiber. In this work, fibers of these systems are post-processed using a CO2 laser to segregate the flux and recrystallize the GaAs. The volatility and incongruency of the GaAs are shown to make in-fiber single crystal growth complex, with thermal and structural limitations of the borosilicate glass cladding also influencing the process. Despite these challenges, the GaAs:flux fibers were successfully segregated in the lateral, longitudinal, and radial directions, demonstrating the first steps towards in-fiber devices with GaAs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
As metallic additive manufacturing grew in sophistication, users have requested greater control over the systems, namely the ability to fully change the process parameters. The goal of this ...manuscript is to review the effects of major process parameters on build quality (porosity, residual stress, and composition changes) and materials properties (microstructure and microsegregation), and to serve as a guide on how these parameters may be modified to achieve specific design goals for a given part. The focus of this paper is on laser powder bed fusion, but elements can be applied to electron beam powder bed fusion or direct energy deposition techniques.
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•Comparison between laser welding and laser-based additive manufacturing parameters is established.•Major process parameters during laser-based additive manufacturing and their influence are discussed.•Remedies for avoid several problems found during additive manufacturing are proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The emergence of bulk metallic glasses and their identification as versatile advanced engineering materials with attractive properties has led to a surge in research efforts to investigate processing ...methods, which can be used either to synthesise new BMG alloys or to shape BMG workpieces into final components with specific geometries. Among such technologies, the number of studies focussing on the laser processing of BMGs has gradually increased over the past decade. For this reason, a comprehensive summary of the state-of-the-art in this particular field of research is presented in this review. The reported studies are categorised into the different laser applications that have been proposed so far by the research community, namely the welding, cladding, additive layer manufacturing, micro machining and microstructure modification of BMG substrates. Due to the attractive properties of BMGs stemming from their amorphous nature, results are also presented, when available, concerning the effect of laser irradiation on the generation of crystalline precipitates during processing and the effect of these changes on the resulting material properties. This review has identified a number of gaps in the knowledge surrounding the laser processing of bulk metallic glasses. Understanding the fundamental interaction of laser energy with multi-component alloys will be necessary, as the development of lasers continues and the amount of available bulk metallic glasses increases. In particular, the crystallisation kinetics of bulk metallic glasses during laser irradiation needs to be understood to aid in the development and optimisation of processes such as welding and cladding. This could be helped by created an accurate simulation model to predict the onset of crystallisation although this is not a minor challenge, developing a complete temperature field model during laser irradiation is a complex task when considering vaporisation, plasma effects as well as chemical composition changes in the material. Besides, there is also the issue of variations in material properties as the temperature increases, particularly for BMGs whose temperature dependent properties are not well-documented. The research into the additive layer manufacturing of bulk metallic glass should continue to grow. Parametric effects need to be addressed to complete the optimisation of this process. Further investigations of the resulting crystallisation processes upon repeated melting and solidification should also aid in the process being able to be controlled more effectively. Finally, the use of laser processing of bulk metallic glass for specific application needs to be investigated further.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•The CHF and HTC of modified surfaces are much higher than that of smooth surface.•The enhanced wickability is not the only mechanism of CHF enhancement for FC-72.•A modified model of CHF mechanism ...was proposed.•The CHF on both smooth and modified surfaces can be explained well by the model.
In the present study, the pool boiling heat transfer of micro/nano hierarchically structured surfaces, as well as that of a smooth surface in gas dissolved FC-72 (the subcooling is 1 K) was studied. Femtosecond laser processing was used to fabricate the structured surfaces. It was found that for the surfaces with small processing spacing (LS30 and LS70, where the number after LS specifies the spacing in μm), the critical heat flux (CHF) showed almost no increase, while the heat transfer coefficient (HTC) was enhanced noticeably compared to that of a smooth surface (SS). For LS100, LS200, LS200-2 (compared to LS200, LS200-2 has the same processing spacing but a much higher peak-to-valley height), LS400 and LS800, both the CHF and HTC were enhanced remarkably compared to those of SS. The maximum HTC enhancement was obtained for LS70, with the HTC being 5.87 times larger than that of SS. The most remarkable increase in the CHF was achieved for LS200-2, with an improvement of 91% relative to that of SS. The liquid supply mechanism at the CHF of the micro/nano hierarchically structured surfaces was investigated. A modified model taking into account the coalesced bubble departure frequency, Jakob number and capillary wicking effects was proposed for CHF prediction. The CHF data from this study and the literature were used to validate the model, and it was found that the predicted results agree quite well with the experimental data within ±8%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The basic principles and characteristics of the CPL processing method are systematically introduced.•How the CPL method is for precisely and efficiently material processing is analyzed.•The recent ...advancements the CPL processing are analyzed.•A summary and outlook of the CPL technology is also highlighted.
With wide applicability and low-cost processing advantages, laser processing, as a mature and versatile tool, is forming an alternative to conventional processing technologies. In recent years, the global laser market ushered in a broad new demand since the gradual increase in the penetration rate of laser processing in consumer electronics, automotive processing, aerospace, medical and other fields. Ultrafast laser and continuous wave (CW) laser are the representatives of high-quality and high-efficiency in laser processing, respectively, but it is a huge challenge to achieve high-quality and high-efficiency laser processing at the same time in the true sense, which has been the goal of the joint efforts of scientific researchers in recent decades. In this context, combined pulse laser (CPL), one of the hybrid laser processing technologies, has proven to be a reliable tool for the high-quality and high-efficiency processing through the processing advantages of different types of lasers and controlling the laser-matter interaction. In this review, the basic principles and characteristics of the CPL processing method are systematically introduced. Also, how the CPL method is for precisely and efficiently ablating, drilling, welding and structuring and their recent advancements are analyzed. Finally, a summary and outlook of the CPL technology is highlighted.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Laser-based methodologies for synthesis, reduction, modification and assembly of graphene-based materials are highly demanded for energy-related electrodes and devices for portable electronics. Laser ...technologies for graphene synthesis and modification exhibit several advantages when compared to alternative methods. They are fast, low-cost and energy saving, allowing selective heating and programmable processing, with controlled manipulation over the main experimental parameters. In this review, we summarize the most recent studies on laser-assisted synthesis of graphene-based materials, as well as their modification and application as electrodes for supercapacitor and battery applications. After a brief introduction to the physical properties of graphene and a discussion of the different types of laser processing operations, the practical uses of laser techniques for the fabrication of electrode materials are discussed in detail. Finally, the review is concluded with a brief discussion of some of the outstanding problems and possible directions for research in the area of laser-based graphene materials for energy storage devices.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The morphology and structural transformation of 6H-SiC under irradiation of single pulse with varying energies was investigated. Three distinct modification regimes were identified based on pulse ...energy.•At low pulse energies just above the modification threshold, the sample surface undergoes moderate modification, no larger craters and amorphous silicon are produced. At even higher energies, nonlinear absorption and ionization occur under ultrafast laser irradiation, Si-C crystal bonds are broken and melting, resolidification and the generation of amorphous and crystalline silicon phase appeared.•Tunneling ionization and avalanche ionization are responsible for the generation of free electrons in SiC sample and melting/resolidification happens when a large portion of energy is transferred from electrons to the lattice.
Silicon carbide (SiC) is promising in semiconductor devices operating in extreme environments owing to its excellent properties including wide forbidden band, high thermal conductivity, thermal stability, chemical inertness, and high saturation rate. However, its Mohs hardness of 9 poses challenges for conventional machining techniques. Femtosecond laser processing offers an effective alternative for SiC processing, yet the underlying mechanism of interaction between laser pulse and SiC remains unclear. Herein we studied the mechanism of laser interacted with SiC, thoroughly investigated the structural transformation and morphology change of single crystal 6H-SiC induced by single ultrafast laser pulse irradiation at different pulse energies. The morphology changes of single pulse induced crater, i.e., diameter and depth, are characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The structural transformation and changes in the chemical composition are analyzed using micro-Raman spectroscopy. Moreover, the evolution of lattice arrangement is revealed by high-resolution transmission electron microscopy (TEM). At low pulse energies just above the modification threshold, the sample surface undergoes moderate modification, no larger craters and amorphous silicon are produced. At even higher energies, nonlinear absorption and ionization occur under ultrafast laser irradiation, the energy of the hot free electrons is transferred to the cold crystal lattice through electron–phonon scattering, causing a sharp increase in the lattice temperature. Si-C crystal bonds are broken and melting, resolidification and the generation of amorphous and crystalline silicon phase appeared.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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