Additive manufacturing letters最新文献_第3页

3D-printed carbon fiber meta-skins for impact mitigating sandwich structures 3d打印碳纤维元皮肤，用于减轻夹心结构的冲击

IF 4.7 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-10-30 DOI: 10.1016/j.addlet.2025.100337

Sean Eckstein , Sophia Benkirane , George Youssef

The intersection between additive manufacturing and metamaterials reinvigorated the pursuit of optimal protective structures in civilian and military applications by challenging the process-structure-performance nexus. This letter introduces a novel subclass of mechanical metamaterials, termed meta-skins, which are printed with continuous carbon fiber composites in pseudo-woven patterns to achieve higher impact efficacy-to-weight ratios. High-performance elastomeric foam cores were adhered to the carbon fiber meta-skins in two configurations: monocoque and sandwich. The impact efficacy was evaluated using direct impact loading scenarios at 4.43 m/s and 15 m/s, respectively, using a fully instrumented drop tower and a small-scale shock tube. Digital image correlation (DIC) revealed the full-field kinematics of deformation as a function of strain rate. Postmortem failure analysis cross-referenced the dynamic mechanical behavior with the failure modes, epitomizing the interrelation between sample configuration and impact efficacy. Generally, monocoque structures outperformed their sandwich counterparts under low-velocity impacts, whereas the opposite was observed under moderate-velocity loading conditions, such that the performance of the sandwich structures surpassed that of the monocoque structures in nearly all dynamic evaluation metrics. Moreover, the meta-skin-capped specimens outperformed their cross-ply benchmarks by 15 % under similar impact events, demonstrating the novelty of the newly introduced subclass of metamaterials. The research outcomes unlock the scientific and technological potential of the next generation of protective armors by leveraging advanced weaving and fiber materials.

增材制造和超材料之间的交叉通过挑战工艺-结构-性能关系，重新激活了对民用和军事应用中最佳防护结构的追求。这封信介绍了一种新的机械超材料子类，称为meta-skin，它是用伪编织图案的连续碳纤维复合材料印刷的，以实现更高的冲击效率-重量比。高性能弹性体泡沫芯以两种结构粘接在碳纤维元皮上：单体结构和夹层结构。在4.43 m/s和15 m/s的直接冲击载荷情况下，使用全仪器仪表的跌落塔和小型激波管分别评估了冲击效果。数字图像相关（DIC）揭示了变形作为应变速率函数的全场运动。事后失效分析交叉引用了动态力学行为和失效模式，体现了试样形态与冲击效能之间的相互关系。总体而言，单壳结构在低速冲击下的性能优于夹层结构，而在中速加载条件下则相反，在几乎所有的动力评价指标中，夹层结构的性能都优于单壳结构。此外，在类似的冲击事件下，超皮肤覆盖的样品比交叉层基准高出15%，证明了新引入的超材料子类的新颖性。研究成果通过利用先进的编织和纤维材料，解锁了下一代防护装甲的科学和技术潜力。

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引用次数: 0

Isolating the influence of residual stress on tensile behaviour of laser-based powder bed fusion Ti alloys via mechanical stress relief 通过机械应力释放分离残余应力对激光基粉末床熔合钛合金拉伸行为的影响

IF 4.7 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-10-28 DOI: 10.1016/j.addlet.2025.100336

Zhiyi Zou , Brandon McWilliams , Brady Butler , Alexander Butler , Richard Hague , Marco Simonelli

This study proposes a mechanical stress relief (MSR) process to reduce the residual stress in PBF-LB materials. It involves progressive, slow cyclic loading in the material’s elastic region. Two Ti alloys, Ti-6Al-4V and Ti-7Cr-4Sn, were chosen as model alloys and underwent MSR accordingly. Results suggest that the proposed MSR helps reduce residual stress, and its effectiveness in relieving residual stress is similar across the two alloys. However, the influence of MSR on the tensile performance is different in the two alloys, which is affected by the initial residual stress level and the material’s deformation mechanism. Ti-6Al-4V possesses high residual stress, with deformation slip being the only deformation mechanism. In contrast, Ti-7Cr-4Sn possesses relatively low residual stress, and a unique deformation mechanism involves {332}<113> twinning and ω_iso precipitates. Such a unique deformation mechanism leads to crack initiation driven by twin-confined dislocation pile-up.

本研究提出了一种机械应力消除（MSR）工艺来降低PBF-LB材料的残余应力。它涉及材料弹性区域的渐进、缓慢循环加载。选择Ti- 6al - 4v和Ti- 7cr - 4sn两种钛合金作为模型合金，进行MSR试验。结果表明，所提出的MSR有助于降低残余应力，并且其消除残余应力的效果在两种合金中是相似的。然而，MSR对两种合金拉伸性能的影响是不同的，这受初始残余应力水平和材料变形机制的影响。Ti-6Al-4V具有较高的残余应力，变形滑移是其唯一的变形机制。相比之下，Ti-7Cr-4Sn具有相对较低的残余应力，其独特的变形机制涉及{332}<；113>；孪晶和ωiso析出。这种独特的变形机制导致双约束位错堆积驱动裂纹萌生。

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引用次数: 0

Ultrasonic nanocrystal surface modification for post-processing of additively manufactured AISI 440C stainless steel 增材制造AISI 440C不锈钢后处理的超声纳米晶表面改性

IF 4.7 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-10-22 DOI: 10.1016/j.addlet.2025.100335

Milad Zohrevand , Reza Jafari , Venkata K. Nadimpalli , Thomas Dahmen , Sherzod Barlibayev , Khasan Turkmenov , Bakhadir Mirzaev , Auezhan Amanov

Laser-based powder bed fusion (L-PBF) method has been shown as a promising method in additive manufacturing (AM) of the AISI 440C stainless tool steel. Nevertheless, the as-printed material typically exhibits a soft austenitic structure, poor surface finish, and tensile residual stresses, all of which limit its mechanical performance. In this study, ultrasonic nanocrystal surface modification (UNSM) was applied as a post-processing treatment to improve the mechanical and surface properties of as-built AISI 440C l-PBF samples. The UNSM treatment resulted in a 26 % increase in surface hardness, a 50 % reduction in surface roughness, and a transition of tensile residual stress (57 MPa) into compressive residual stress (−364 MPa). Microstructural analysis revealed that nano-grain formation, increased dislocation density, strain-induced martensitic transformation, and carbide precipitation were the key mechanisms responsible for surface hardening. These findings demonstrate the potential of UNSM as an effective post-processing method for enhancing the performance of l-PBF-manufactured AISI 440C components.

基于激光的粉末床熔合（L-PBF）方法是一种很有前途的增材制造（AM）方法。然而，印刷材料通常表现为软奥氏体结构，表面光洁度差，拉伸残余应力，所有这些都限制了其机械性能。本研究采用超声纳米晶表面改性（UNSM）作为后处理，改善了AISI 440C l-PBF样品的力学性能和表面性能。UNSM处理导致表面硬度提高26%，表面粗糙度降低50%，拉伸残余应力（57 MPa）转变为压缩残余应力（- 364 MPa）。微观组织分析表明，纳米晶粒的形成、位错密度的增加、应变诱导马氏体相变和碳化物的析出是导致表面硬化的主要机制。这些发现表明，UNSM作为一种有效的后处理方法，可以提高l- pbf制造的AISI 440C组件的性能。

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引用次数: 0

Computed axial lithography of multioxide glasses and ceramics from nanoparticles and organic–inorganic precursors 用纳米颗粒和有机-无机前驱体制备多氧化物玻璃和陶瓷的轴向光刻技术

IF 4.7 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-10-14 DOI: 10.1016/j.addlet.2025.100334

Leonhard Hambitzer , Richard Prediger , Yaxuan Sun , Joseph Toombs , Zahra Hosneolfat , Ramin Montazeri , Sebastian Kluck , Hayden K. Taylor , Frederik Kotz-Helmer

Computed axial lithography is a volumetric additive manufacturing technique offering layer-free structuring and high fabrication speed by projecting a dynamic light pattern into a volume of photocurable resin. Ceramic and glass processing could benefit from this technology, as many applications, such as optics or bone grafts, require 3D structuring. However, developing suitable resins is challenging as high transparency of the photocurable resins is a necessity and standard particle-based resins are typically not transparent. In this study, we explored three novel approaches to fabricate transparent resins for structuring multioxide glasses and ceramics using computed axial lithography. The resins were composed of an acrylate-based binder and contained either nanoparticles, nanoparticles with an organic–inorganic precursor or only organic–inorganic precursors, as the glass or ceramic sources. The prints were thermally converted into pure glass or ceramic. We demonstrated this process for bioactive glass, bioactive calcium phosphate ceramic, and transparent titanium dioxide-doped silica glass. Microscaffolds were fabricated, and each material system was characterized regarding its suitability for computed axial lithography. This work expands the range of available computed axial lithography materials for microstructuring of functional multioxide glasses and ceramics.

计算轴向光刻是一种体积增材制造技术，通过将动态光模式投射到可光固化的树脂中，提供无层结构和高制造速度。陶瓷和玻璃加工可以从这项技术中受益，因为许多应用，如光学或骨移植，都需要3D结构。然而，开发合适的树脂是具有挑战性的，因为光固化树脂必须具有高透明度，而标准的颗粒基树脂通常不透明。在这项研究中，我们探索了三种新的方法来制造透明树脂结构的多氧化物玻璃和陶瓷使用计算机轴向光刻。该树脂由丙烯酸酯基粘合剂组成，并含有纳米颗粒、有机-无机前驱体或仅有机-无机前驱体的纳米颗粒作为玻璃或陶瓷源。这些版画被热转化为纯玻璃或陶瓷。我们在生物活性玻璃、生物活性磷酸钙陶瓷和透明二氧化钛掺杂二氧化硅玻璃上展示了这一过程。制备了微支架，并对每种材料系统进行了表征，以确定其适合于计算机轴向光刻。这项工作扩大了可用于功能多氧化物玻璃和陶瓷微结构的计算机轴向光刻材料的范围。

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引用次数: 0

Bimetallic 17-4 PH/316 L stainless steel: Interfacial diffusion and mechanical response in multi-material MEX 双金属17-4 PH/ 316l不锈钢：多材料MEX中的界面扩散和力学响应

IF 4.7 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-10-13 DOI: 10.1016/j.addlet.2025.100332

Héctor García de la Torre, Giovanni Gómez-Gras, Marco A. Pérez

Multi-material additive manufacturing enables the integration of distinct alloys with contrasting mechanical and microstructural properties, such as stainless steels 17–4 PH and AISI 316 L that are widely used in aerospace and tooling, within a single build; however, their combined performance in hybrid configurations remains underexplored. Here, we address key challenges related to densification, interfacial behavior and mechanical property control of metallic multi-material additive manufacturing structures. Near-full densification (98–99 %) was achieved with strong interfacial bonding and minimal deformation. Microstructural analysis revealed solid-state diffusion of Ni and Mo from 316 L into 17–4 PH, resulting in a chemically and structurally graded interface that affects local phase composition and fracture mechanics. Mechanical testing under tensile and flexural loading demonstrated that configurations with 17–4 PH as face material and 316 L as the core provided higher stiffness and strength while maintaining ductility, with flexural property metrics more than double to those of monolithic 316 L cores. Fractographic analysis confirmed that fractures initiated within the more brittle 17–4 PH material and often thereafter propagated along the interface, identifying it as a mechanically weaker zone serving as a crack pathway. These results highlight the potential hybrid stainless steel structures to achieve combined mechanical responses suitable for advanced engineering applications in a single manufacturing step, enabling the design of cost-efficient, multifunctional components for structural applications requiring hybrid mechanical behavior.

多材料增材制造能够在一次构建中集成具有不同机械和微观结构性能的不同合金，例如广泛用于航空航天和模具的17-4 PH不锈钢和AISI 316 L不锈钢；然而，它们在混合配置中的综合性能仍未得到充分研究。在这里，我们解决了与金属多材料增材制造结构的致密化、界面行为和力学性能控制相关的关键挑战。接近完全致密化（98 - 99%），界面结合强，变形最小。显微组织分析表明，Ni和Mo从316 L向17-4 PH的固相扩散，形成了一个化学和结构梯度界面，影响了局部相组成和断裂力学。拉伸和弯曲载荷下的力学测试表明，采用17-4 PH作为表面材料，316l作为芯材的配置在保持延展性的同时提供了更高的刚度和强度，其弯曲性能指标是单片316l芯材的两倍以上。断口学分析证实，裂缝起源于更脆的17-4 PH材料，随后经常沿着界面扩展，将其确定为机械较弱的区域，作为裂缝路径。这些结果突出了混合不锈钢结构的潜力，可以在单个制造步骤中实现适合高级工程应用的组合机械响应，从而为需要混合机械行为的结构应用设计成本效益高的多功能组件。

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引用次数: 0

Suppression of the leading-edge bulge effect in ceramic vat photopolymerization via yield stress regulation for enhanced part performance 通过屈服应力调节抑制陶瓷还原釜光聚合中前缘凸起效应以提高零件性能

IF 4.7 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-10-13 DOI: 10.1016/j.addlet.2025.100333

Ning Wang , Chi Zhang , Hai Chang , Dongxu Yao , Zirong Zhai , Rui Yang

This study addresses the "leading-edge bulge effect" encountered during the ceramic slurry recoating stage in ceramic vat photopolymerization by regulating the slurry’s yield stress to suppress backflow. A three-dimensional network structure was constructed using Carbomer 940 as a thickening agent, thereby enhancing the slurry’s yield stress. A combined approach of numerical simulation and experimental validation was employed to evaluate the impact of yield stress modulation on liquid level control and part performance. When the thickener concentration reached ≥2 %, backflow was effectively suppressed, resulting in stable slurry leveling and intact surface quality of printed parts. Under these conditions, the average flexural strength reached a peak value of 928.59 MPa, comparable to that of conventionally sintered silicon nitride. However, excessive thickener content further restricted backflow but led to insufficient slurry coverage, adversely affecting the fabrication of complex geometries. These findings demonstrate that yield stress optimization is critical for achieving a balance between print quality and mechanical performance, offering theoretical guidance for process refinement in ceramic vat photopolymerization.

本研究通过调节陶瓷浆体的屈服应力来抑制回流，解决了陶瓷浆体光聚合中陶瓷浆体重涂阶段遇到的“前缘凸起效应”。以卡波姆940为增稠剂，构建了三维网络结构，从而提高了浆料的屈服应力。采用数值模拟和实验验证相结合的方法，评估了屈服应力调制对液位控制和零件性能的影响。当增稠剂浓度达到≥2%时，回流得到有效抑制，浆液流平稳定，打印件表面质量完好。在此条件下，平均抗弯强度达到峰值928.59 MPa，与常规烧结氮化硅相当。然而，过量的增稠剂含量进一步限制了回流，但导致浆体覆盖不足，对复杂几何形状的制造产生不利影响。这些发现表明，屈服应力优化对于实现打印质量和机械性能之间的平衡至关重要，为陶瓷大桶光聚合的工艺改进提供了理论指导。

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引用次数: 0

Effect of interface orientation in laser powder bed fusion of IN718/GRCop-42 bimetallic parts for Aerospace 航空航天用IN718/GRCop-42双金属件激光粉末床熔接界面取向的影响

IF 4.7 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-10-12 DOI: 10.1016/j.addlet.2025.100331

Alasdair Bulloch , Amanda Cruchley , Allin Groom , Andy Harris , Fiona Schulz , Christopher J. Tuck , Richard Hague , Marco Simonelli

Additive manufacturing of bimetallic parts has gathered significant interest in recent years. Of particular relevance is the combination of Ni-based superalloys and Cu-based alloys suitable for high temperature applications, such as those found in aerospace rocket engines. To provide confidence in the production of such bimetallic parts, a detailed understanding of the process-structure relationship is required. This study investigates the effect of deposition sequence and recoating direction on the interfacial microstructure evolution in samples where material is graded through horizontal, vertical and angled interfaces. The samples in this study are produced through laser powder bed fusion of IN718 and GRCop-42, using a Schaeffler Aerosint selective powder deposition recoater. Analysis was conducted through a combination of backscatter electron imaging, x-ray diffraction, energy dispersive spectroscopy, and electron backscatter diffraction. For a horizontal interface, the deposition sequence has a significant effect on the presence of defects and phase formation at the interface. The recoating direction is shown to have an influence on the mixing behaviour for vertical and angled interfaces, with a gradual transition of the alloys produced when the interface is aligned parallel to the recoating direction. In contrast either a significant crossing of the first-deposited material across the interface occurs, or a sudden change in composition develops when deposition is perpendicular to the interface. On the basis of these findings, design rules can be developed to ensure the fabrication of suitably designed bimetallic parts for high temperature applications such as rocket engines in the aerospace sector.

近年来，双金属零件的增材制造引起了人们的极大兴趣。特别相关的是适用于高温应用的镍基高温合金和铜基合金的组合，例如在航空航天火箭发动机中发现的合金。为了对这种双金属部件的生产提供信心，需要对工艺结构关系有详细的了解。本研究考察了沉积顺序和重涂方向对水平、垂直和倾斜界面梯度试样中界面微观结构演变的影响。本研究的样品是使用舍弗勒Aerosint选择性粉末沉积重涂器，通过激光粉末床熔融IN718和GRCop-42制备的。通过背散射电子成像、x射线衍射、能量色散光谱和电子背散射衍射相结合的方法进行分析。对于水平界面，沉积顺序对界面缺陷的存在和相的形成有显著影响。重涂方向对垂直界面和倾斜界面的混合行为有影响，当界面平行于重涂方向时，合金的过渡逐渐发生。相反，要么是第一次沉积的材料在界面上发生明显的交叉，要么是当沉积垂直于界面时，成分突然发生变化。在这些发现的基础上，可以制定设计规则，以确保制造适合设计的双金属部件，用于高温应用，如航空航天领域的火箭发动机。

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引用次数: 0

Physics-informed machine learning surrogate for scalable simulation of thermal histories during wire-arc directed energy deposition 在电弧定向能沉积过程中，为可扩展的热历史模拟提供物理信息的机器学习替代品

IF 4.7 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-10-08 DOI: 10.1016/j.addlet.2025.100327

Michael Ryan, Mohammad Hassan Baqershahi, Hessamoddin Moshayedi, Elyas Ghafoori

Wire-arc directed energy deposition (DED) has emerged as a promising additive manufacturing (AM) technology for large-scale applications. However, the complex thermal dynamics inherent to the process present challenges in ensuring structural integrity and mechanical properties of fabricated components. Finite element method (FEM) simulations have been conventionally employed to predict thermal history during deposition. However, their high computational demand increase significantly with scale. Given the necessity of multiple repetitive simulations for heat management and the determination of optimal printing strategy, FEM simulation quickly becomes unfit. Instead, advancements have been made in using trained neural networks as surrogate models for rapid prediction. However, traditional data-driven approaches necessitate large amounts of relevant and verifiable external data, either from simulation, experimental, or analytical solutions, during the training and validation of the neural network. Regarding large-scale wire-arc DED, none of these data sources are readily available in quantities sufficient for an accurate surrogate. The introduction of physics-informed neural networks (PINNs) has opened up an alternative simulation strategy by leveraging the existing physical knowledge of the phenomena with advanced machine learning methods. However, the practical application of PINNs for real-world large-scale wire-arc DED has been rarely explored, particularly within the context of structural engineering. This study investigates one of the necessary steps for up-scaling PINN with a focus on advanced and effective sampling of collocation points — a critical factor controlling both the training time and the performance of the model. The results affirm the potential of PINNs to outperform FEM in terms of wall-clock times, while maintaining the desired accuracy and offering resolution-agnostic evaluation. Further discussion provides an outlook on the future steps for improving the PINNs for wire-arc DED simulations.

线弧定向能沉积（DED）已成为一种有前景的大规模增材制造（AM）技术。然而，复杂的热动力学固有的过程提出了挑战，以确保结构完整性和机械性能的制造组件。传统上采用有限元法（FEM）模拟来预测沉积过程中的热历史。然而，它们的高计算需求随着规模的增加而显著增加。考虑到热管理和最佳打印策略的确定需要多次重复模拟，有限元模拟很快变得不适合。相反，在使用训练有素的神经网络作为快速预测的替代模型方面取得了进展。然而，在神经网络的训练和验证过程中，传统的数据驱动方法需要大量相关且可验证的外部数据，无论是来自仿真、实验还是分析解决方案。对于大规模的线弧DED，这些数据来源都不容易获得足够数量的准确替代。物理信息神经网络（pinn）的引入，通过利用现有的物理知识和先进的机器学习方法，开辟了一种替代的模拟策略。然而，pin在现实世界大规模线弧DED中的实际应用很少被探索，特别是在结构工程的背景下。本研究探讨了扩展PINN的必要步骤之一，重点是高级和有效的搭配点采样-这是控制训练时间和模型性能的关键因素。结果证实了pinn在壁钟时间方面优于FEM的潜力，同时保持所需的精度并提供与分辨率无关的评估。进一步的讨论展望了改进线弧DED模拟pin的未来步骤。

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引用次数: 0

Additive friction stir deposition of multi-layer aluminum-silicon carbide metal matrix composites 添加剂搅拌摩擦沉积多层铝-碳化硅金属基复合材料

IF 4.7 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-10-04 DOI: 10.1016/j.addlet.2025.100330

Robert C. Pack , John W. Bohling , Joshua Kincaid , Abrian Abir , Tony Schmitz , Brett G. Compton

Aluminum metal matrix composites (MMCs) possess good strength and stiffness combined with low density, making them attractive in a variety of applications. Additive friction stir deposition (AFSD) is a relatively new, solid state metal additive manufacturing process that has high potential as a forming route for MMCs of complex shape. However, little work has been done to investigate how AFSD affects microstructure and properties of conventional MMCs. In this work, aluminum-silicon carbide (Al-SiC) MMC extruded plate was used as feedstock for AFSD to create a five-layer deposit of an Al-SiC MMC for characterization. Microstructure, particle size distribution, and hardness were evaluated in the as-deposited condition while hardness recovery was investigated with post-deposition solution and aging heat treatments. The deposited MMC revealed complex, macroscale mixing behavior, mild fragmentation of the SiC particles, and uniform particle size distribution and dispersion across MMC regions of the deposit. Solution and aging heat treatment restored the hardness of the deposited MMC to that of the as-received feedstock. This work suggests AFSD is a promising route for producing complex MMC parts with similar or better properties to those produced by traditional processes.

金属铝基复合材料（MMCs）具有良好的强度和刚度，且密度低，具有广泛的应用前景。添加剂搅拌摩擦沉积（AFSD）是一种相对较新的固态金属增材制造工艺，作为一种复杂形状的金属复合材料的成形途径具有很高的潜力。然而，很少有人研究AFSD如何影响传统mmc的微观结构和性能。在这项工作中，铝-碳化硅（Al-SiC） MMC挤压板被用作AFSD的原料，以创建一个五层沉积的Al-SiC MMC进行表征。研究了沉积状态下的显微组织、粒度分布和硬度，并研究了沉积后固溶和时效热处理的硬度恢复情况。沉积的MMC表现出复杂的宏观混合行为，SiC颗粒轻度破碎，粒度分布均匀，在MMC区域内分散。固溶和时效热处理使沉积的MMC的硬度恢复到原料的硬度。这项工作表明，AFSD是一种有前途的路线，用于生产复杂的MMC部件，具有与传统工艺生产的部件相似或更好的性能。

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引用次数: 0

In situ recrystallization of pure Cu during electron beam powder bed fusion 纯铜在电子束粉末床熔合过程中的原位再结晶

IF 4.7 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-10-04 DOI: 10.1016/j.addlet.2025.100329

Alexandre Margueret , Pierre Lhuissier , Guilhem Martin

Additively manufactured parts often exhibit an anisotropic microstructure characterized by columnar grains resulting from epitaxial growth from the underlying layers in the direction of the thermal gradient, i.e. parallel to the build direction. Herein we report that the columnar grains of pure Cu produced by electron beam powder bed fusion can be transformed into equiaxed grains by reducing the hatch spacing and increasing the scanning speed. Columnar grains are observed for hatch spacings ≥ 100 µm and a scanning speed = 100 mm/s, whereas equiaxed grains are observed when the hatch spacing is ≤ 60 µm and the scanning speed ≥ 150 mm/s. The underlying mechanism is discussed and identified on the basis of EBSD analyses. It is concluded that in situ recrystallization during electron beam powder bed fusion can be locally activated by varying the processing parameters. Further insight into the underlying mechanism is gained from the characterization of layered samples produced with varying processing parameters along the build direction. We show that in situ recrystallization offers an interesting pathway to produce site-specific microstructures in electron beam powder bed fusion.

增材制造的零件通常表现出各向异性的微观结构，其特征是柱状晶粒是由下层在热梯度方向（即平行于构建方向）的外延生长引起的。本文报道了通过减小舱口间距和提高扫描速度，电子束粉末床熔合产生的纯Cu柱状晶粒可以转变为等轴晶粒。当舱口间距≥100µm，扫描速度= 100 mm/s时，观察到柱状晶粒；当舱口间距≤60µm，扫描速度≥150 mm/s时，观察到等轴晶粒。在EBSD分析的基础上，讨论并确定了其潜在机制。结果表明，改变工艺参数可以局部激活电子束粉末床熔合过程中的原位再结晶。从沿着构建方向的不同处理参数产生的分层样品的表征中获得了对潜在机制的进一步了解。我们发现原位再结晶为电子束粉末床熔合中产生特定位置的微结构提供了一个有趣的途径。

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引用次数: 0