激光技术在材料加工领域的应用与发展

激光因其具有方向性强、能量密度高、时间和空间控制性好等特点,在航天航空、汽车制造、电子电器和生物医疗等领域获得广泛应用,尤其在材料加工领域。简要介绍了激光加工技术的原理及优势,主要从组织性能研究、工艺开发与优化、数值模拟等方向综述了激光技术在切割、焊接、增材制造和表面改性4个加工领域的研究进展和应用现状,表明超短超快激光技术的发展进一步促进了激光技术在材料加工领域的纵深应用,并对激光技术未来发展进行展望。     

聚醚醚酮材料改性、 加工与应用

聚醚醚酮(PEEK)及其复合材料在航空、汽车、医疗等领域具有很大的应用市场。通过增强改性,聚醚醚酮材料力学、热学等性能得到了很好提升,利用熔融挤出机、注塑成型机以及3D打印机等成型装备,将聚醚醚酮及其复合材料制备成不同类型的产品,以适用不同领域的材料需求。从聚醚醚酮的改性方法、制品成型制备以及主要应用领域3个方面,简要介绍了近些年国内外学者的研究工作与研究重点。     

选择性激光烧结用原材料研究进展

文章阐述了当前快速原型技术中选择性激光烧结材料的国内外研究现状,包括金属材料、聚合物材料、陶瓷材料等。重点提出新型材料木塑复合材料的研究现状,指出基于木塑复合材料的低成本、可降解和可循环使用等优点,它将成为SLS未来发展的趋势。     

Selective Chemical Modification of Graphene Surfaces: Distinction Between Single‐ and Bilayer Graphene

Graphene modifications with oxygen or hydrogen are well known in contrast to carbon attachment to the graphene lattice. The chemical modification of graphene sheets with aromatic diazonium ions (carbon attachment) is analyzed by confocal Raman spectroscopy. The temporal and spatial evolution of surface‐adsorbed species allows accurate tracking of the chemical reaction and identification of intermediates. The controlled transformation of sp² to sp³ carbon proceeds in two separate steps. The presented derivatization is faster for single‐layer graphene and allows controlled transformation of adsorbed diazonium reagents into covalently bound surface derivatives with enhanced reactivity at the edge of single‐layer graphene. On bilayer graphene the derivatization proceeds to an adsorbed intermediate, which reacts slower to a covalently attached species on the carbon surface.     

磁性材料超快动力学研究与飞秒抽运探测技术

阐述了磁性材料的重要性及其超快过程研究中存在的问题,对飞秒抽运探测(Pump-probe)技术的试验方法和原理进行了论述.介绍了飞秒抽运探测技术对磁性材料中磁化动力学过程的研究现状,以及抽运探测在磁性材料研究中的新发展--对磁致伸缩材料中的磁化动力学过程研究、对材料复介电常数的测定和光学探针技术的引入,为磁性材料的应用和磁化动力学研究提供了新的方向.     

适用加工包装材料的激光技术

在通常的卷筒式加工机械及制造过程中,往往需要处理那些不容易转变加工的材料,其中包括的加工工序有模切、切边、切槽或切口等,此时,一种十分适用的新型加工方法就是应用激光切割技术。在软包装材料,例如,纸张纸板、塑料薄膜及复合箔片等制造业中,使用激光技术标志着包装技术创新方面已迈出了一大步,因而这项新技术正在不断地得到普及,而且还在继续完善和发展。激光技术是在二十世纪五十年代     

Direct Slicing Based on Material Performance and Process Parameters for Selective Laser Sintering

Direct slicing from GAD models to generate sectional contours of the part to be sintered for Selective Laser Sintering （SLS） may overcome inherent disadvantages of using a Stereo Lithography （STL） format. In this paper, a direct slicing procedure is proposed for Selective Laser Sintering based on material performance and process parameters. Slicing thickness depends on the 3 D geometric model, material performance and process parameters. The relationship among material performance, process parameters and the largest slicing thickness is established using analysis of a sintering temperature field. A dynamic linked library is developed to realize direct slicing from a CAD model.     

Improving Biocompatibility of Implantable Metals by Nanoscale Modification of Surfaces: An Overview of Strategies,Fabrication Methods,and Challenges

The human body is an intricate biochemical–mechanical system, with an exceedingly precise hierarchical organization in which all components work together in harmony across a wide range of dimensions. Many fundamental biological processes take place at surfaces and interfaces (e.g., cell–matrix interactions), and these occur on the nanoscale. For this reason, current health‐related research is actively following a biomimetic approach in learning how to create new biocompatible materials with nanostructured features. The ultimate aim is to reproduce and enhance the natural nanoscale elements present in the human body and to thereby develop new materials with improved biological activities. Progress in this area requires a multidisciplinary effort at the interface of biology, physics, and chemistry. In this Review, the major techniques that have been adopted to yield novel nanostructured versions of familiar biomaterials, focusing particularly on metals, are presented and the way in which nanometric surface cues can beneficially guide biological processes, exerting influence on cellular behavior, is illustrated. Frontispiece adapted from Reference 94 .

     

Direct Laser Patterning of Soft Matter: Photothermal Processing of Supported Phospholipid Multilayers with Nanoscale Precision

Direct laser patterning of supported phospholipid multilayers is investigated. Spin coating is used to fabricate stacked bilayers of 1,2‐dioleoyl‐sn‐glycero‐3‐phosphate (DOPA). Photothermal processing with a focused laser beam at λ = 514 nm allows removal of the coating at predefined positions without causing any significant change in adjacent areas. Moreover, processing with nanoscale precision is feasible despite the soft and fluid nature of phospholipid films. In particular, holes with diameters from 1.8 µm down to 300 nm and below are fabricated by using a 1/e² laser spot size of about 2.5 µm. In addition, patterning is also very flexible and can be carried out over macroscopic length scales and at short processing times. Considering these features photothermal laser processing constitutes a powerful tool for micro‐ and nanopatterning of phospholipid films.     

FeSiAl微波衰减材料激光3D打印技术研究

为适应新型微波真空电子器件对微波衰减材料“薄、轻、宽、强”的发展需求,解决传统人工涂敷和烧结无法精确控制涂层厚度的问题,本文提出了使用3D打印SLM技术制备FeSiAl涂层的新思路。首先,筛选出SLM成型后衰减性能最好的FeSiAl合金粉末;其次,研究3D打印工艺参数对成型件衰减性能的影响规律。研究表明,选择200目以细、Fe∶Si∶Al∶O的质量百分比为74.63∶11.64∶3.36∶10.37的FeSiAl合金粉末,取3D打印的工艺参数为激光功率175 W、扫描速度1600mm/s、扫描间距0.06 mm、铺粉厚度0.02 mm,预热温度为80℃,可制备出具有优异微波衰减性能的FeSiAl涂层,较好地满足器件设计及制造需求。     

理化所三维金属纳米结构飞秒激光加工获重要进展

中科院理化技术研究所段宣明团队、日本理化学研究所河田聪团队通过合作,近日在利用飞秒激光多光子纳米加工技术进行三维微纳结构制备的研究中获得重要进展,成功突破了光学衍射极限,实现了纳米尺度的三维金属纳米结构加工.     

Surface Modification of Fluorine-Doped Tin Oxide Thin Films Using Femtosecond Direct Laser Interference Patterning: A Study of the Optoelectronic Performance

Transparent conductive oxides (TCOs) are used in solar cells not only to extract photogenerated carriers but also to allow sunlight to reach the photoactive material. Therefore, controlling the electrical and optical properties of such oxides is crucial for the optimization of the efficiency of solar cells. Herein, direct laser interference patterning (DLIP) method is used to control the surface morphology, optical and electrical properties of fluorine-doped tin oxide (FTO) by applying femtosecond laser pulses. The topography characterization reveals periodic line-like microstructures with a period of 3.0 μm and average heights between 20 and 185 nm, depending on the applied laser fluence levels. Laser-induced periodic surface structures are observed on the valleys of the texture aligned perpendicularly to the laser radiation polarization. A relative increase in the average total and diffuse optical transmittance up to 5% and 500%, respectively, is obtained in the 400–800 nm spectral range as a consequence of the generated micro- and nanostructures. Calculations of two figures of merit suggest that the texturing of FTO might enhance the efficiency of solar cells, in particular dye-sensitized (DSSCs). The findings of this study confirm that DLIP is a convenient technique for structuring electrodes for highly efficient optoelectronic devices.     

Creation,Recording, and Processing of Information When Forming the Information Resources of Solid-State Structures Using the Methods of Optical Spectroscopy

An analysis was made of the process of forming the information resource of solid-state structures in optical spectroscopy during the stages of creating and recording information. The advantages of Fourier spectroscopy are indicated and an information measuring facility based on a Fourier spectrometer is described.     

纳米结构金属氧化物定向合成与功能设计组装

介绍了几种具有重要应用价值的纳米结构金属氧化物定向合成与纯化技术，包括发光材料专用氧化铝深度脱铁技术、氧化铝／氧化镁／氧化锌等金属氧化物微粒形状控制、尺寸控制、核-壳结构控制等；讨论了不同控制技术在发光材料、陶瓷墨水打印材料、特殊催化剂载体材料、射线／静电防护材料和芯片／光盘抛光材料等领域的具体应用及不同金属氧化物组装方式对材料性能的影响。     

金刚石涂层激光抛光机理及加工工艺研究进展

CVD金刚石涂层表面粗糙度高、颗粒大,不能满足精密和超精密加工的要求,在一定程度上制约了其发展和应用,降低CVD金刚石涂层表面粗糙度是迫切需要解决的难题.阐述了激光抛光CVD金刚石涂层机理,对比了微观抛光和宏观抛光的差异,总结了国内外激光抛光金刚石涂层研究进展,探讨了 目前激光抛光金刚石涂层的挑战和亟待解决的难点.     

激光快速成形技术的发展及其在功能梯度材料制备上的应用

激光快速成形技术集计算机辅助设计、高功率激光熔覆、快速成形于一体,通过激光熔化同步输送的金属或陶瓷粉末,在基板上逐层熔化堆积而形成致密的材料或零件.其离散/堆积的成形特点使得该技术在材料及零件制备上具有很大的柔性,通过精确控制2种或多种材料粉末的输送和相应的工艺可以实现材料组成、微观组织结构和性能的梯度分布及多种材料的集成.介绍了激光快速成形的原理、技术特点、系统组成,着重介绍了国内外采用该技术在制备功能梯度材料方面的研究开发情况,简要分析了利用激光快速成形技术制备功能梯度材料的发展前景.     

激光拼焊侧围加强板用材分析及性能控制技术

目的研究某车型侧围加强板生产稳定性的材料性能。方法通过对某车型激光拼焊侧围加强板的主要用材TRIP800进行分析,研究不同3种生产批次材料性能和组织上的差异性,包括化学成分、显微组织、残余奥氏体含量、扩孔试验、力学性能、表面粗糙度的测量。结果 3种不同批次材料生产后,两种批次满足生产稳定要求,一种批次不能满足稳定生产要求,识别了TRIP800材料影响零件冲压开裂的关键性能指标,主要为材料伸长率及硬化指数。结论针对某侧围加强板的生产稳定性,材料伸长率大于25%,硬化指数n值不低于0.18的情况下,能够满足稳定生产。扩孔试验结果表明,该零件的成形过程中,扩孔率并不是唯一影响开裂的性能指标。     

重型燃气轮机定向结晶叶片的材料与制造工艺

重型燃气轮机是我国能源发展战略中的关键装备. 在高温和热腐蚀环境下工作的透平叶片,是重型燃机的核心热端部件.与航空发动机叶片比较,先进重型燃气轮机透平叶片,在高温热腐蚀环境下长期工作,而且叶片的尺寸较大,因此,对叶片使用的高温合金材料及其制造工艺均提出了特殊的要求.用于燃气轮机叶片的抗热腐蚀高温合金材料,经历了从多晶到定向和单晶的发展历程,其合金在设计中具有高Cr,高Ti,Al比等几个显著区别于航空发动机叶片材料的特征.兼顾高强度、优异抗热腐蚀性能及长期组织和性能稳定性的燃气轮机用铸造高温合金的研发,因此更具挑战.定向凝固是重型燃气轮机用大型定向结晶叶片制造工艺中最为关键的技术之一.介绍了先进定向凝固技术——高温度梯度液态金属冷却定向凝固技术的发展,对比了不同定向凝固工艺对高温合金典型组织及力学性能的影响,并简单介绍了我国近期在大型定向结晶叶片研制方面的进展.