金属零件3D打印技术的应用研究

金属零件3D打印技术作为整个3D打印体系中最为前沿和最具潜力的技术,是目前先进制造技术的重要发展方向。随着科技发展对材料的不断需求,利用快速成形技术直接制造金属功能零件将会成为该技术的主要发展方向。3D打印技术正在快速改变着人们传统的生产方式和生活方式。以数字化、网络化、个性化、定制化为特点的3D打印制造技术被外界认为将推动第三次工业革命。激光工程化净成形技术(LENS),激光选区熔化技术(SLM)及电子束选区熔化技术(EBSM)3种技术是金属零件3D打印技术的典型代表。对金属零件3D打印技术,包括基本的技术原理及其技术应用领域进行了介绍,最后对金属零件3D打印技术的发展进行了展望。     

3D打印主要成形工艺及其应用进展

3D打印是以计算机图形数据为基础,通过逐层堆积的方式构建实体,具有高柔性制造以及对复杂零件自由快速成形的特点.从文献研究入手,重点介绍了光固化成形、熔融沉积制造、选区激光烧结、选区激光熔化、三维印刷成形、分层实体制造等典型3D打印工艺的成形原理以及研究进展,在此基础上着重概述了3D打印在生物医学、航空航天、建筑工程领域的应用.简要分析了当前3D打印技术发展中存在的一些问题并提出了一系列解决方案.3D打印技术的出现,给传统制造技术带来了革命性改变,其应用范围广泛,未来一定会融入到人们生活的方方面面.     

粉末钛合金3D打印技术研究进展

粉末钛合金3D打印技术以低成本、易成形、柔性化制备、零件性能优异等优势,近年来成为钛合金近净成形制造领域的研究热点。总结了国内外粉末钛合金3D打印技术的研究进展,包括激光熔化沉积成形技术(LMD)、激光选区熔化成形技术(SLM)、电子束选区熔化成形技术(SEBM)。比较研究了3种成形技术制备的钛合金的组织特点及力学性能,并讨论了粉末钛合金3D打印技术的市场化现状与未来发展趋势。     

陶瓷3D打印技术及材料研究进展

综述了陶瓷3D打印技术和材料的特性及其研究进展与应用现状,重点讨论了喷墨打印技术、熔化沉积成型技术、光固化成型技术、分层实体制造技术、激光选区熔化技术/激光选区烧结技术、三维打印成型技术、浆料直写成型技术的特性和研究进展,分析了磷酸三钙陶瓷、氧化铝陶瓷、陶瓷先驱体、SiC陶瓷、Si_3N_4陶瓷、碳硅化钛陶瓷的特性和应用现状,最后指出了陶瓷3D打印技术的发展方向是与传统陶瓷工艺相结合,实现陶瓷制品的快速生产及生物陶瓷制品、高性能陶瓷功能零件的制造。     

SLM金属3D打印技术在主泵样机试验中的应用研究

金属3D打印工艺具有材料利用率高,易成型复杂结构,柔性定制化生产等优点,适合于模型级试验叶轮、导叶、诱导轮及其它金属功能件的快速制造。其中,选区激光熔化成型技术(SLM)作为主流的金属3D打印技术,可以获得冶金结合、组织致密、高尺寸精度和良好力学性能的零件。采用SLM技术,进行了某项目主泵缩尺试验样机叶轮和导叶的直接成型,材料为17-4PH不锈钢。其中叶轮与组装轴一体化打印,节省了组装成本,对打印模型优化、加工参数和过程监控等工艺问题进行研究,保证了一体化轴叶轮部件和大直径导叶的成功打印,并对打印后的零件进行了热处理和精加工,最后进行了主泵样机气液两相性能试验。试验结果表明,SLM金属3D打印技术制造的转、定子部件成功应用于主泵样机试验中,明显缩短样机加工周期,加工精度、表面质量和力学性能等指标均满足试验要求。     

3D打印技术研究现状和关键技术EI北大核心CSCD

本文首先简要介绍了3D打印技术的基本原理及分类,然后重点介绍了有关金属材料3D打印的几种方法:电子束熔化成形(EBM)、激光选区熔化成形(SLM)、激光快速成形技术(LDMD)。简述了金属材料3D打印的应用领域及国内外发展情况及研究现状。文章最后结合国内外金属材料3D打印的研究现状,指出金属材料3D打印需要在打印用粉末、金属3D打印设备、3D打印零件无损检测方法、3D打印零件的失效行为和寿命预测等方面进行重点研究,并建立3D打印零件的无损检测标准规范以及3D打印材料全面力学性能数据库。     

基于粉末成形的激光增材制造陶瓷技术研究进展

陶瓷以其优异的热物理化学性能在航空航天、能源、环保以及生物医疗等领域具有极大的应用潜力。随着这些领域相关技术的快速发展, 其核心零件部件外形结构设计日益复杂、内部组织逐步走向定制化、梯度化。陶瓷具有硬度高、脆性大等特点, 较难通过传统的加工成形方法实现异形结构零件的制造, 最终限制了陶瓷材料的工程应用范围。激光增材制造技术作为一种快速发展的增材制造技术, 在复杂精密陶瓷零部件的制造中具有显著优势: 无模、精度高、响应快以及周期短, 同时能够实现陶瓷零件组织结构灵活调配, 有望解决上述异形结构陶瓷零件成形问题。本文综述了多种基于粉末成形的激光增材制造陶瓷技术: 基于粉末床熔融的激光选区烧结和激光选区熔化; 基于定向能量沉积的激光近净成形技术。主要讨论了各类激光增材陶瓷技术的成形原理与特点, 综述了激光选区烧结技术中陶瓷坯体后处理致密化工艺以及激光选区熔化和激光近净成形技术这两种技术中所打印陶瓷坯体基体裂纹开裂行为分析及其控制方法的研究进展, 对比分析了激光选区烧结、激光选区熔化以及激光近净成形技术在成形陶瓷零件的技术特征, 最后展望了激光增材制造陶瓷技术的未来发展趋势。     

粉末床电子束3D打印Ti-6Al-4V合金的工程应用技术研究进展

电子束选区熔化(selective electron beam melting,SEBM)是20世纪90年代初期发展起来的一类金属3D打印工艺,具有能量利用率高、成形效率高和成形应力低的突出优点,并且是在真空环境中成形,特别适用于高熔点、高活性、脆性金属材料复杂构件的高质量制造。由于其是一种粉末床熔融型3D打印工艺,通常也称之为粉末床电子束3D打印技术。从粉末床电子束3D打印的粉末原料、组织与性能、复杂构件的成形能力和工程应用等方面,介绍了作者团队10多年来在粉末床电子束3D打印稀有金属材料方面的工作积累,重点介绍了粉末床电子束3D打印Ti-6Al-4V合金的研究进展,最后结合3D打印技术整体发展趋势对粉末床电子束3D打印技术的发展前景和重点发展方向进行了展望。     

金属零件3D打印技术研究进展

金属零件3D打印技术是整个3D打印体系中最为前沿和最有潜力的技术,是增材制造的重要发展方向。简述了3D打印工艺中适用于金属材料的工艺,主要包括选择性激光烧结(SLS)技术、选择性激光熔化(SLM)技术、选择性激光熔覆(SLC)技术、层叠法成型(LOM)技术、电子束熔覆技术。讨论了各工艺特征、存在问题以及研究进展。     

同轴送粉金属激光3D打印熔池流动、成分分布以及组织生长数值模拟的研究进展

在“中国制造2025”、美国《国家先进制造战略计划》、欧洲航天局《惊奇计划》、日本《增材制造科研计划》、新加坡《工业增材制造项目》以及欧盟《3D打印标准化路线图》等全球新型制造技术迅猛发展的机遇下,金属激光3D打印融合了计算机辅助设计、材料加工与成形技术,以数字化模型文件为基础,通过软件与数控系统将特制材料逐层堆积固化,制造出实体产品,该技术日益成为国内外专家学者的研究热点。它与传统的对原材料进行切削、组装的加工模式不同,是通过材料累加的原理,从无到有地制造产品的新型技术工艺。也正是由于增材制造的这种技术特点,使得它受到全球的广泛关注,将可能会给传统的制造业带来一系列深刻的变革。其中同轴送粉式金属激光3D打印技术因具有成形尺寸大、可利用材料范围广、成形件的材料性能优异等特点,在航空航天、交通、医疗与能源等领域有着广阔的应用前景,成为金属增材制造主流的工艺技术。 3D打印熔池中存在着传热、对流、传质、气-液界面冶金反应以及固-液界面扩散等复杂的动态物理冶金过程。熔池的流体力学行为直接影响材料组织的均匀性以及致密性,因此,如何通过流体力学方法对熔池的流体动态过程进行模拟,建立熔池温度和流场的三维非稳态模型,并定量分析浮力、表面张力、粉末冲击力以及综合作用对3D打印过程温度场、速度场和熔池形态的影响是需要解决的关键问题。 数值仿真模拟是研究同轴送粉式金属激光3D打印熔池动力学过程的重要手段之一。目前,在关于同轴送粉式金属激光3D打印数值模拟和激光焊的数值模拟研究中,已包含较为全面的多尺度数值模型,例如光-粉耦合作用数值模型、熔池气-液界面和固-液混合区界面追踪模型、熔池瞬时变化的热场和流场分析模型、熔池中合金元素的分布过程介观模型以及基于相场法的熔池形貌和显微组织凝固元胞自动机模型等。 本文主要阐述国内外研究学者对同轴送粉式金属激光3D打印仿真模拟的研究进展,主要集中在3D打印过程中熔池瞬时变化的热场和流场分析、合金元素的分布过程以及熔池形貌和显微组织凝固等方面。由于数值模拟方法具有一定的通用性,为了更全面地介绍与同轴送粉式金属激光3D打印技术相关的数值模拟方法,本文也涉及了少量送粉式激光熔覆以及激光电弧填粉焊接等过程的数值模拟工作。     

Nickel-titanium shape memory alloys made by selective laser melting:a review on process optimisation

Selective laser melting (SLM) is a mainstream powder-bed fusion additive manufacturing (AM) process that creates a three-dimensional (3D) object using a high power laser to fuse fine particles of various metallic powders such as copper, tool steel, cobalt chrome, titanium, tungsten, aluminium and stainless steel. Over the past decade, SLM has received significant attention due to its capability in producing dense parts with superior mechanical properties. As a premier shape memory alloy, the nickel-titanium (NiTi) shape memory alloy is attractive for a variety of biomedical applications due to its superior mechanical properties, superelasticity, corrosion resistance and biocompatibility. This paper presents a comprehensive review of the recent progress in NiTi alloys produced by the SLM process, with a particular focus on the relationship between processing parameters, resultant microstructures and properties. Current research gaps, challenges and suggestions for future research are also addressed.The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00376-9     

3D打印制备多孔结构的研究与应用现状

多孔结构材料具有优异的物理、力学性能,应用领域广泛。目前,已开发出的多孔结构的制备方法种类繁多,然而仅少数可实现批量生产,大多数方法工艺较为复杂,并且在制备过程中难以对多孔结构进行有效控制,以致所得多孔结构仍存在某些性能方面的不足。3D打印技术的发展与应用为多孔结构的制备带来了新的途径,所制备的多孔结构可同时具备宏观孔隙和微观孔隙,其骨架及宏观孔隙可以根据需要进行设计。可用于制备多孔结构的3D打印方法主要有利用激光能量的选择性激光烧结法(SLS)、选择性激光熔化法(SLM)和激光近净成形法(LENS)等方法,利用电子束能量的电子束熔化(EBM)法,喷射粘结剂的三维印刷(3DP)法,材料挤出类中的熔融沉积成形(FDM)法和三维浆丝沉积(3DF)法,以及间接3D打印法。近年来,国内外学者对采用这些方法制备多孔结构开展了一定的研究,以期找到适合具体情况的3D打印方法及相应合理的工艺规范,从而提高制件的性能。采用SLS、SLM和LENS法,通过控制激光扫描轨迹和粉末烧结程度可以获得材料的宏观和微观孔隙。SLS法可制备的多孔结构材料种类较广,SLM和LENS法主要用于制备金属多孔结构。EBM法与SLM法类似,但EBM法需要在真空环境下成形,可用于制备Ti等活泼金属材料。适用于3DP法的粉末材料种类更广,可选用不同的粘结剂和相应的后处理方法,其工艺灵活性大。FDM法一般用于低熔点热塑性材料,通过熔融挤出而堆积成宏观多孔结构。3DF法以粉末浆料的形式挤出成形,适用的材料种类比FDM法广,得到的结构具有宏观和微观孔隙。FDM和3DF法的打印精度和孔隙尺寸受喷嘴打印能力的限制。间接法先利用某种便捷的3D打印方法制备出多孔结构原模,再将该原模经粉末冶金、浇注等方法制得所需的多孔结构材料,这样可以避免3D打印直接制备某些材料的多孔结构在结构特征方面受到的限制。上述这些方法中,由于激光和电子束的能量集中,故SLM和EBM法制备的多孔结构相对于其他方法更精细。3D打印制备多孔结构时孔隙的形成机理可以总结为:制件内打印轨迹未到达的区域形成的宏观设计孔隙、制件骨架内的粘结剂被加热分解或被溶解而去除后形成的孔隙、气体溶解在烧结过程中的熔融金属内形成的孔隙、激光扫描熔迹之间形成的孔隙、粉末颗粒间堆积空隙形成的孔隙。本文对3D打印制备多孔结构的研究与应用现状进行了综述,概述了制备多孔结构的几种主要的3D打印方法,总结了其孔隙的形成机理,介绍了3D打印多孔结构的应用现状,指出了未来需要开展的研究。     

Powder bed binder jet 3D printing of Inconel 718: Densification,microstructural evolution and challenges☆

Traditional manufacturing of Inconel 718 components from castings and thermomechanical processing routes involve extensive post processing and machining to attain the desired geometry. Additive manufacturing (AM) technologies including direct energy deposition (DED), selective laser melting (SLM), electron beam melting (EBM) and binder jet 3D printing (BJ3DP) can minimize scrap generation and reduce lead times. While there is extensive literature on the use of melting and solidification based AM technologies, there has been limited research on the use of binder jet 3D printing. In this paper, a brief review on binder jet additive manufacturing of Inconel 718 is presented. In addition, existing knowledge on sintering of Inconel 718 has been extended to binder jet 3D printing. We found that supersolidus liquid phase sintering (SLPS) is necessary to achieve full densification of Inconel 718. SLPS is sensitive to the feedstock chemistry that has a strong influence on the liquid volume fraction at the processing temperature. Based on these results, we discuss an empirical framework to determine the role of powder particle size and liquid volume fraction on sintering kinetics. The role of powder packing factor and binder saturation on microstructural evolution is discussed. The current challenges in the use of BJ3DP for fabrication of Inconel 718, as well as, extension to other metal systems, are presented.     

基于多喷头并联的3D打印机控制系统的研究

针对现有的单喷头3D打印机在打印大体积模型或零件时打印时间长、打印精度低等问题,提出了一种基于多喷头并联的3D打印机控制系统的设计方法,实现在模型切片平面的多轨迹并联打印。设计了光固化树脂并联打印喷头;采用主从式系统结构,以双STM32F407ZGT为核心、双PCL6045BL和CPLD（complex programable logic device,复杂可编程逻辑器件）为控制终端,搭建了一套双CPU （central processing unit,中央处理单元）的嵌入式3D打印机硬件控制系统;基于喷头切向跟踪原理和等间距打印原则,推导了二轴-四轴插补数据转换算法,实现了“二轴”轨迹数据到“四轴”插补加工数据的转换;设计了并联打印数据预处理程序、并联打印控制程序和并联打印脉冲输出控制程序以实现多轨迹并联打印控制;进行了控制系统的实验测试,对比了多喷头并联与单喷头3D打印机的实际打印效果。结果表明：与传统的单喷头打印方式相比,采用多喷头并联打印方式可以显著提高打印效率和打印精度,且打印质量较好。研究结果为大体积打印件的快速加工成型提供了一种切实可行的解决方案,具有一定的实用价值。     

3D printing metals like thermoplastics: Fused filament fabrication of metallic glasses

Whereas 3D printing of thermoplastics is highly advanced and can readily create complex geometries, 3D printing of metals is still challenging and limited. The origin of this asymmetry in technological maturity is the continuous softening of thermoplastics with temperature into a readily formable state, which is absent in conventional metals. Unlike conventional metals, bulk metallic glasses (BMGs) demonstrate a supercooled liquid region and continuous softening upon heating, analogous to thermoplastics. Here we demonstrate that, in extension of this analogy, BMGs are also amenable to extrusion-based 3D printing through fused filament fabrication (FFF). When utilizing the BMGs’ supercooled liquid behavior, 3D printing can be realized under similar conditions to those in thermoplastics. Fully dense and amorphous BMG parts are 3D printed in ambient environmental conditions resulting in high-strength metal parts. Due to the similarity between FFF of thermoplastics and BMGs, this method may leverage the technology infrastructure built by the thermoplastic FFF community to rapidly realize and proliferate accessible and practical printing of metals.     

A review on selective laser sintering/melting (SLS/SLM) of aluminium alloy powders: Processing,microstructure, and properties

Manufacturing businesses aiming to deliver their new customised products more quickly and gain more consumer markets for their products will increasingly employ selective laser sintering/melting (SLS/SLM) for fabricating high quality, low cost, repeatable, and reliable aluminium alloy powdered parts for automotive, aerospace, and aircraft applications. However, aluminium powder is known to be uniquely bedevilled with the tenacious surface oxide film which is difficult to avoid during SLS/SLM processing. The tenacity of the surface oxide film inhibits metallurgical bonding across the layers during SLS/SLM processing and this consequently leads to initiation of spheroidisation by Marangoni convection. Due to the paucity of publications on SLS/SLM processing of aluminium alloy powders, we review the current state of research and progress from different perspectives of the SLS/SLM, powder metallurgy (P/M) sintering, and pulsed electric current sintering (PECS) of ferrous, non-ferrous alloys, and composite powders as well as laser welding of aluminium alloys in order to provide a basis for follow-on-research that leads to the development of high productivity, SLS/SLM processing of aluminium alloy powders. Moreover, both P/M sintering and PECS of aluminium alloys are evaluated and related to the SLS process with a view to gaining useful insights especially in the aspects of liquid phase sintering (LPS) of aluminium alloys; application of LPS to SLS process; alloying effect in disrupting the surface oxide film of aluminium alloys; and designing of aluminium alloy suitable for the SLS/SLM process. Thereafter, SLS/SLM parameters, powder properties, and different types of lasers with their effects on the processing and densification of aluminium alloys are considered. The microstructure and metallurgical defects associated with SLS/SLM processed parts are also elucidated by highlighting the mechanism of their formation, the main influencing factors, and the remedial measures. Mechanical properties such as hardness, tensile, and fatigue strength of SLS/SLM processed parts are reported. The final part of this paper summarises findings from this review and outlines the trend for future research in the SLS/SLM processing of aluminium alloy powders.     

增材制造金属玻璃的研究进展

金属玻璃(即非晶合金)具有较高的强度、硬度和耐磨性,优异的耐腐蚀性能等,目前已被广泛应用于制备棒球杆、传感器、电磁铁芯、变压器等。增材制造(即3D打印)技术集节约材料、可个性化定制复杂几何件优点于一身,现被广泛研究和应用。目前已掀起了3D打印金属玻璃的研究热潮。本文主要综述了3D打印金属玻璃的研究进展,在此基础上探讨了其存在的问题以及解决办法。采用优化的工艺参数和扫描策略可部分避免这些问题,对热影响区的温度分布与工艺参数之间的关系模拟研究是解决3D打印成形致密块体金属玻璃问题的关键。     

Fabrication and properties of TiC-high manganese steel cermet processed by 3D gel printing

Journal of Materials Science - 3D printing is attractive for the fabrication of complex, three-dimensional parts from metallic powder based on a computer-aided design model. Here, we report an...     

Two-Way 4D Printing: A Review on the Reversibility of 3D-Printed Shape Memory Materials

The rapid development of additive manufacturing and advances in shape memory materials have fueled the progress of four-dimensional (4D) printing. With the right external stimulus, the need for human interaction, sensors, and batteries will be eliminated, and by using additive manufacturing, more complex devices and parts can be produced. With the current understanding of shape memory mechanisms and with improved design for additive manufacturing, reversibility in 4D printing has recently been proven to be feasible. Conventional one-way 4D printing requires human interaction in the programming (or shape-setting) phase, but reversible 4D printing, or two-way 4D printing, will fully eliminate the need for human interference, as the programming stage is replaced with another stimulus. This allows reversible 4D printed parts to be fully dependent on external stimuli; parts can also be potentially reused after every recovery, or even used in continuous cycles—an aspect that carries industrial appeal. This paper presents a review on the mechanisms of shape memory materials that have led to 4D printing, current findings regarding 4D printing in alloys and polymers, and their respective limitations. The reversibility of shape memory materials and their feasibility to be fabricated using three-dimensional (3D) printing are summarized and critically analyzed. For reversible 4D printing, the methods of 3D printing, mechanisms used for actuation, and strategies to achieve reversibility are also highlighted. Finally, prospective future research directions in reversible 4D printing are suggested.