Additive manufacturing letters最新文献_第7页

A generalized mechanical blocking criterion for the columnar-to-equiaxed transition during additive manufacturing 增材制造过程中柱向等轴过渡的广义机械阻塞准则

IF 4.2 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-05-28 DOI: 10.1016/j.addlet.2025.100290

Christopher A. Hareland , Maria-Ioanna T. Tzini , Florian Hengsbach , Gregory B. Olson , Peter W. Voorhees

We present a fully general model for the columnar-to-equiaxed transition (CET) that extends the classical mechanical blocking models to completely arbitrary nucleation-undercooling distributions and dendrite growth laws. The general approach is compared to the classical models for a recently reported die steel developed for additive manufacturing (AM). Notably, the models employ a completely pre-characterized and physically motivated set of material parameters, i.e., the kinetic coefficients and nucleation parameters. A method of calculating the nucleation parameters using CALPHAD (CALculation of PHAse Diagrams) software is also demonstrated and discussed. The general model can directly utilize this full distribution of nucleation parameters, as well as the full dendrite growth law obtained from a CALPHAD-coupled model that incorporates non-equilibrium kinetic effects in multicomponent alloys. Finally, a morphology selection map is constructed for the printable die steel to predict regions of equiaxed dendritic, columnar dendritic, and plane-front solidification, showing that the general model of the CET provides higher fidelity in predicting regions of columnar and equiaxed solidification, and that tailoring the inoculant particle-size distribution is a viable method of controlling the CET under AM processing conditions.

我们提出了一个完全通用的柱状到等轴转变（CET）模型，将经典的机械阻塞模型扩展到完全任意的成核-过冷分布和枝晶生长规律。将该方法与最近报道的用于增材制造（AM）的模具钢的经典模型进行了比较。值得注意的是，这些模型采用了一套完全预先表征和物理驱动的材料参数，即动力学系数和成核参数。本文还讨论了用相图计算软件CALPHAD计算成核参数的方法。通用模型可以直接利用成核参数的完整分布，以及多组分合金中包含非平衡动力学效应的calphad耦合模型获得的完整枝晶生长规律。最后，构建了可打印模具钢的形态选择图，用于预测等轴枝晶、柱状枝晶和平面凝固区域，结果表明，通用模型在预测柱状枝晶和等轴凝固区域方面具有较高的保真度，并且在增材制造条件下，调整孕育剂粒径分布是控制等轴凝固区域的可行方法。

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引用次数: 0

A practical guide to hydrogel working curves for bioprinting 生物打印水凝胶工作曲线的实用指南

IF 4.2 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-05-22 DOI: 10.1016/j.addlet.2025.100293

Rion J. Wendland , Thomas J. Kolibaba , Kristan S. Worthington , Jason P. Killgore

The working curve is a widely implemented, but presently not standardized, method of assessing resin printability for photopolymer additive manufacturing technologies. While the working curve has been studied and refined for plastic resins, application to hydrogel materials used in bioprinting has been limited. Hydrogels present measurement challenges due to their decreased solids content, compliant nature, and significant swelling. Here, adapting lessons learned from interlaboratory studies on plastic working curves, we assess various techniques for hydrogel working curve measurements. Notably, across several formulations with various molecular weights and solids content, hydrogels exhibit near ideal log-linear behavior consistent with the Jacobs model when measured appropriately. However, certain measurement modalities (such as contact-based and rheological) can indicate Jacobs-like behavior, but with systematic errors in the cure depth compared to non-contact optical methods. Overall, this work highlights the challenges when conducting hydrogel working curve measurements and provides several considerations to help further develop and standardize measurements across 3D bioprinting applications.

工作曲线是一种广泛实施的方法，但目前尚未标准化，用于评估光聚合物增材制造技术的树脂可打印性。虽然已经研究和改进了塑料树脂的工作曲线，但在生物打印中使用的水凝胶材料的应用受到限制。水凝胶由于其固体含量降低、柔顺性和明显的膨胀性，给测量带来了挑战。在这里，根据实验室间对塑料工作曲线的研究经验，我们评估了水凝胶工作曲线测量的各种技术。值得注意的是，在具有不同分子量和固体含量的几种配方中，水凝胶在适当测量时表现出接近理想的对数线性行为，与Jacobs模型一致。然而，某些测量方式（如基于接触和流变）可以显示雅各布斯行为，但与非接触光学方法相比，在固化深度上存在系统误差。总的来说，这项工作强调了在进行水凝胶工作曲线测量时所面临的挑战，并提供了一些考虑因素，以帮助进一步开发和标准化3D生物打印应用中的测量。

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引用次数: 0

Effectiveness of residual stress and pores on the β-grain refinement in L-PBF Ti6Al4V processed with hot isostatic pressing 残余应力和孔隙对热等静压L-PBF Ti6Al4V β晶粒细化的影响

IF 4.2 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-05-15 DOI: 10.1016/j.addlet.2025.100291

Vivek K Sahu , Hector R. Siller , M.H. Herman Shen

The present study examines the effect of HIP (Hot Isostatic Pressing) treatment above the β-transus temperature on porosity reduction and its effect on the transition from columnar to equiaxed prior β-grains in L-PBF (Laser Powder Bed Fusion) Ti6Al4V. HIP treatment was conducted at a holding temperature of 1050 °C and a pressure of 120 MPa for 2 h on the L-PBF Ti6Al4V samples, which were deposited with four different scanning speeds of 300 mm/s, 400 mm/s, 650 mm/s, and 1100 mm/s, while keeping the other deposition parameters constant. The sample with the higher scanning speed (1100 mm/s) exhibits the highest area fraction of lack-of-fusion defects, leading to more pronounced equiaxed β-grain refinement and texture weakening compared to the sample that has the lowest scanning speed (300 mm/s) and negligible lack-of-fusion defect. During the HIP treatment, the local stresses around the sharp tips of the defects, along with the inherent residual stresses in the as-built samples, contribute to the dynamic recrystallization below and above the β-transus temperature.

本研究考察了热等静压（HIP）处理对L-PBF（激光粉末床熔合）Ti6Al4V中β-横截面温度以上孔隙率降低的影响及其对柱状晶粒向等轴晶粒过渡的影响。在保持L-PBF Ti6Al4V样品在300 mm/s、400 mm/s、650 mm/s和1100 mm/s四种不同扫描速度下，保温温度为1050℃，压力为120 MPa， HIP处理2 h，其余沉积参数不变。较高扫描速度（1100 mm/s）的样品显示出最高的未熔合缺陷面积分数，与最低扫描速度（300 mm/s）的样品相比，其导致的等轴β晶粒细化和织构弱化更为明显。在HIP处理过程中，缺陷尖端周围的局部应力以及构建样品中固有的残余应力有助于在β-横向温度以下和高于β-横向温度的情况下进行动态再结晶。

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引用次数: 0

Continuous carbon fiber 3D printing with interweaving deposition for enhanced mechanical performance in fused filament fabrication 连续碳纤维3D打印与交织沉积，以提高机械性能的熔丝制造

IF 4.2 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-05-09 DOI: 10.1016/j.addlet.2025.100289

A. ElSherbiny, A.J. Qureshi, P. Mertiny

Additive manufacturing (AM) has revolutionized modern manufacturing by enabling the rapid prototyping and production of complex geometries with minimal material waste. Among AM techniques, Fused Filament Fabrication (FFF) is widely used for polymer-based manufacturing but exhibits limitations in high-performance applications due to insufficient mechanical properties. To address these shortcomings, this study focuses on advancing a standard FFF system to integrate Continuous Carbon Fiber (CCF) and implement interweaving deposition patterns, with the goal of enhancing structural performance and integrity. Representative volume element modeling and finite element analysis were conducted to evaluate the mechanical behavior, with results validated through experimental mechanical testing. The results confirm that CCF reinforcement improves the mechanical performance of printed components, particularly in the raster direction, although variations in response highlight the influence of material imperfections and non-linearities. The study demonstrates the potential of advanced CCF 3D printing in addressing the limitations of traditional FFF and provides insights for further advancements in polymer composite AM.

增材制造（AM）通过在最小的材料浪费下实现复杂几何形状的快速原型和生产，彻底改变了现代制造业。在增材制造技术中，熔融长丝制造（FFF）广泛用于基于聚合物的制造，但由于机械性能不足，在高性能应用中受到限制。为了解决这些缺点，本研究着重于推进一种标准的FFF系统，以集成连续碳纤维（CCF）并实现交织沉积模式，以提高结构性能和完整性。通过具有代表性的体元建模和有限元分析对其力学行为进行了评价，并通过实验力学试验对结果进行了验证。结果证实，CCF增强提高了印刷部件的机械性能，特别是在光栅方向上，尽管响应的变化突出了材料缺陷和非线性的影响。该研究展示了先进的CCF 3D打印在解决传统FFF局限性方面的潜力，并为聚合物复合材料AM的进一步发展提供了见解。

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引用次数: 0

Multimaterial 3D printing of structured surfaces for increased hydrophobicity of biocomposite materials 用于增加生物复合材料疏水性的结构表面的多材料3D打印

IF 4.2 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-05-08 DOI: 10.1016/j.addlet.2025.100286

Kayah St. Germain , Damien Marchand , Laurence Chocinski-Arnault , Hani E. Naguib , Fabienne Touchard

Material extrusion 3D printing is an up-and-coming additive manufacturing method that is continuously being explored for its many benefits including rapid prototyping, high degree of customizability, and low material waste production, among others. One of the most widely used materials in material extrusion 3D printing is polylactic acid (PLA) due to its ease of printability and bio-origins. Recently, new biofiller reinforced PLA biocomposite filaments have begun being sold commercially, but the introduction of the biofiller creates problems of increased hydrophilicity and hygroscopicity. In this study, a possible solution to this problem was explored by using multimaterial 3D printing to add a thin, structured outer layer to the biocomposite in either pure PLA or TPU. This layer helps limit any external moisture from coming into contact with the underlying biocomposite by creating a barrier with increased hydrophobicity. A grid, triangle, and honeycomb pattern were each tested at 50 %, 75 %, and 100 % pattern densities for each material. It was found that, along with the pattern that was printed, the filament deposition process created additional roughness that influenced the way the water droplets interacted with the surface. All the patterned surfaces displayed a higher water contact angle than when the material was printed in a flat manner. Additionally, factors that influence the feasibility of using this outer structured layer to improve the surface hydrophobicity of biocomposite parts were explored, including material compatibility and adhesion.

材料挤压3D打印是一种新兴的增材制造方法，它的许多优点正在不断被探索，包括快速成型、高度可定制性和低材料浪费等。聚乳酸（PLA）是材料挤出3D打印中应用最广泛的材料之一，因为它易于打印和生物起源。最近，新的生物填料增强PLA生物复合材料长丝已经开始商业化销售，但是引入生物填料会产生亲水性和吸湿性增加的问题。在这项研究中，通过使用多材料3D打印在纯PLA或TPU的生物复合材料中添加薄的、结构化的外层，探索了解决这一问题的可能方法。这一层通过创造一个疏水性增强的屏障，帮助限制任何外部水分与底层生物复合材料接触。网格、三角形和蜂窝图案分别在每种材料的50%、75%和100%的图案密度下进行测试。人们发现，随着打印的图案，细丝沉积过程产生了额外的粗糙度，影响了水滴与表面相互作用的方式。所有的图案表面都显示出比以平面方式印刷时更高的水接触角。此外，还探讨了影响该外层结构层改善生物复合材料部件表面疏水性可行性的因素，包括材料相容性和粘附性。

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引用次数: 0

An activity-based parametric cost analysis for upcycling machining chips to produce feedstock for sustainable additive friction stir deposition 基于作业的切削屑升级回收参数成本分析，以生产可持续添加剂搅拌摩擦沉积的原料

IF 4.2 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-05-08 DOI: 10.1016/j.addlet.2025.100288

Sweta Baruah, Joshua Hoekstra, Tony Schmitz

With the growing emphasis on supply chain resilience and efficiency, manufacturers are increasingly exploring sustainable material reuse strategies. One promising approach is the upcycling of machining chips into usable feedstock for additive friction stir deposition (AFSD), a solid-state additive manufacturing process. AFSD has demonstrated potential for integrating into hybrid manufacturing workflows, offering advantages such as reduced material waste and enhanced process sustainability. However, for chip upcycling to produce AFSD feedstock to be viable, its production cost must be accurately assessed and compared to conventional feedstock options. Estimating these costs poses challenges due to the complexity of the upcycling process and its associated variables. This paper presents a cost modeling framework for the production of upcycled bars from machining chips, specifically as AFSD feedstock. The proposed model incorporates key cost factors such as material preparation, compaction, and processing efficiency. A case study is conducted to compare the cost of upcycled feedstock with commercially available AFSD feedstock, providing insights into the economic feasibility of chip upcycling for AFSD applications.

随着对供应链弹性和效率的日益重视，制造商越来越多地探索可持续的材料再利用策略。一种有前途的方法是将加工芯片升级为添加剂搅拌摩擦沉积（AFSD）的可用原料，这是一种固态增材制造工艺。AFSD已经展示了集成到混合制造工作流程中的潜力，提供了诸如减少材料浪费和增强工艺可持续性等优势。然而，为了使芯片升级回收生产AFSD原料可行，必须准确评估其生产成本，并将其与传统原料选择进行比较。由于升级回收过程及其相关变量的复杂性，估算这些成本带来了挑战。本文提出了一个成本建模框架，用于从加工芯片中生产升级棒，特别是作为AFSD原料。所提出的模型包含了关键的成本因素，如材料制备、压实和加工效率。通过一个案例研究，比较了升级回收原料与商用AFSD原料的成本，为AFSD应用芯片升级回收的经济可行性提供了见解。

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引用次数: 0

Introduction of Cr steels to additive manufacturing using an innovative alloying approach - Challenges and Potentials 采用创新的合金化方法将Cr钢引入增材制造-挑战和潜力

IF 4.2 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-05-03 DOI: 10.1016/j.addlet.2025.100287

Philip König, Sebastian Weber, Jonathan Lentz

This study introduces martensitic Cr steels into additive manufacturing (AM) and provides first important findings for its PBF-LB/M processing. The comprehensive approach covers the entire process chain, including alloy modification, powder production, additive manufacturing, and microstructural characterization. Nitrogen (N), as an interstitial element soluble in iron, plays a central role in this strategy, offering economic and sustainability benefits during powder production while improving the PBF-LB/M-processability and performance of the final components. The atomizing gas N₂ was employed in vacuum induction gas atomization (VIGA) to facilitate direct alloying with N in the powder production process. A thermodynamic calculation-based alloying adjustment of the base alloy resulted in an increased N concentration of approximately 0.17 mass% in the powder. Consequently, electron backscatter diffraction (EBSD) and X-ray diffraction (XRD) studies demonstrate a notable increase in austenite content in the PBF-LB/M state. This finding aligns with thermodynamic predictions regarding the impact of N on austenite stability, reducing the propensity for cold cracking.

本研究将马氏体Cr钢引入增材制造（AM），并为其PBF-LB/M工艺提供了第一个重要发现。全面的方法涵盖了整个工艺链，包括合金改性，粉末生产，增材制造和微观结构表征。氮(N)作为一种可溶于铁的间隙元素，在这一策略中发挥着核心作用，在粉末生产过程中提供经济和可持续效益，同时提高PBF-LB/ m -最终组分的可加工性和性能。采用雾化气体n2进行真空感应气体雾化（VIGA），便于粉末生产过程中与N直接合金化。基于热力学计算的基体合金合金化调整导致粉末中N浓度增加约0.17质量%。因此，电子背散射衍射（EBSD）和x射线衍射（XRD）研究表明，在PBF-LB/M状态下，奥氏体含量显著增加。这一发现与热力学预测一致，即N对奥氏体稳定性的影响，减少了冷裂的倾向。

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引用次数: 0

Toward an Entropy-based Method for Multi-Physics Optimization of Additively Manufactured Cellular Materials 基于熵的增材制造细胞材料多物理场优化方法研究

IF 4.2 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-05-02 DOI: 10.1016/j.addlet.2025.100285

Tyler D. Smith, Dhruv Bhate

This study investigates a novel approach using thermodynamic first principles for optimizing the design of a cellular material for requirements-driven multi-physics, multi-objective optimization. To accomplish this, a generalizable multi-objective optimization method was developed to minimize total exergy destruction as a result of any number of irreversibilities quantified at the level of the unit-cell topology. The method was demonstrated by optimizing the topology of a regular honeycomb to minimize irreversibilities due to thermal losses, fluid friction, mechanical strength, and mass. Using this approach, the method was able to quantitatively optimize the design to minimize thermodynamic irreversibilities and qualitatively understand the interaction between multiple, or individual objective functions to optimize systems for specific use cases. Furthermore, the Relative Exergy Destruction number was proposed as a systematic method for assessing design trade-offs by evaluating the relative contribution of each irreversibility quantified in the optimization.

本研究探讨了一种利用热力学第一原理优化细胞材料设计的新方法，用于需求驱动的多物理场，多目标优化。为了实现这一目标，开发了一种可推广的多目标优化方法，以最大限度地减少因单位胞拓扑级别量化的任意数量的不可逆性而导致的总能量破坏。该方法通过优化规则蜂窝的拓扑结构来证明，以最大限度地减少由于热损失、流体摩擦、机械强度和质量引起的不可逆性。使用这种方法，该方法能够定量地优化设计，以最小化热力学不可逆性，并定性地了解多个或单个目标函数之间的相互作用，以优化特定用例的系统。此外，通过评估优化中量化的每个不可逆性的相对贡献，提出了相对火能破坏数作为评估设计权衡的系统方法。

引用次数: 0

Dimensionless process windows in laser-based powder bed fusion of AISI 316L using ring-shaped beam profiles 基于环形光束轮廓的aisi316l激光粉末床熔合无因次加工窗口

IF 4.2 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-04-28 DOI: 10.1016/j.addlet.2025.100284

Jonas Grünewald, Katrin Wudy

The research trend to investigate the influence of alternative beam profiles on the process and component properties in laser-based powder bed fusion raises the question of how to compare the processes and process results generated with various beam profiles in different sizes. The current state of research mainly examines the process simplified on a single-track basis or addresses isolated aspects, such as the change in beam profile and size with constant absolute process parameters, which neglects the cross-effects of these parameters. Therefore, this paper presents a new approach to consider varied process parameters and their cross effects. The approach is based on a simple heat conduction model and allows the creation of beam shape and size-independent process maps. These dimensionless process maps are created by replacing the common dimensioned process parameters (laser power and scan speed) with combined dimensionless parameters (dimensionless enthalpy and Peclét number, each extended by a dimensionless hatch distance). This way, the parameters consider material and beam properties. Within the process maps, the process boundaries are predicted by simple geometric conditions of the calculated melt pools using the introduced heat conduction model. The model is experimentally validated by conducting a comprehensive parameter study using a multidimensional design of experiments with seven different beam profiles in various sizes and varying laser power, scanning speed, and hatch distance processing AISI 316L. The relative density and surface roughness are evaluated in the experiments. The predicted and experimentally determined process limits are in excellent agreement.

在激光粉末床熔合中，研究不同光束轮廓对工艺和部件性能影响的研究趋势提出了如何比较不同尺寸的不同光束轮廓所产生的工艺和工艺结果的问题。目前的研究主要是考察在单轨基础上简化的过程或处理孤立的方面，例如在恒定的绝对工艺参数下光束轮廓和尺寸的变化，而忽略了这些参数的交叉效应。因此，本文提出了一种考虑不同工艺参数及其交叉效应的新方法。该方法基于简单的热传导模型，并允许创建光束形状和尺寸无关的工艺图。这些无量纲工艺图是通过将常见的有量纲工艺参数（激光功率和扫描速度）替换为组合无量纲参数（无量纲焓和peclsamt数，每个参数都通过无量纲舱口距离扩展）而创建的。这样，参数考虑了材料和梁的特性。在工艺图中，采用引入的热传导模型，通过计算熔池的简单几何条件来预测工艺边界。通过对7种不同尺寸、不同激光功率、扫描速度、不同舱口距离的光束进行多维设计实验，对该模型进行了综合参数研究。在实验中对相对密度和表面粗糙度进行了评价。预测和实验确定的工艺极限非常一致。

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引用次数: 0

Columnar-to-equiaxed transitions in additively manufactured face-centered cubic multi-principal element alloys 增材制造面心立方多主元素合金的柱向等轴转变

IF 4.2 Q2 ENGINEERING, MANUFACTURING

Additive manufacturing letters

Pub Date : 2025-04-14 DOI: 10.1016/j.addlet.2025.100283

Mengyao Zheng , Yu Liao , Zheng Zhou , Hao Zhang , Chuanwei Li , Zhong Long , Jianfeng Gu

Columnar-to-equiaxed transition (CET) represents a critical microstructural characteristic in additively manufactured alloys. Precise control over CET is essential for achieving high-performance metallic components through additive manufacturing. In this study, two face-centered cubic multi-principal element alloys (MPEAs), namely CoCrNi and FeCoCrNi, were fabricated via laser directed energy deposition. The influence of process parameter and alloy composition on the CET of the two MPEAs was investigated. The results demonstrated that pronounced CET phenomena were observed in both MPEAs as the laser power increased and the scanning speed decreased. However, significant variations were noted in their CET parameters, equiaxed grain fraction, and crystallographic texture. Subsequently, the impact of process parameters on temperature gradient, solidification rate, and molten pool morphology was investigated via finite element modelling, revealing the formation mechanisms of the grain morphology and texture in additively manufactured CoCrNi and FeCoCrNi alloys. Additionally, the results of thermodynamic calculation revealed significant differences in the growth restriction factors between the two MPEAs, thereby explaining the distinct CET behaviors observed in the two MPEAs.

柱状到等轴转变（CET）是增材制造合金中一个重要的显微组织特征。通过增材制造实现高性能金属部件，对CET的精确控制至关重要。本研究采用激光定向能沉积法制备了CoCrNi和feccrni两种面心立方多主元素合金（mpea）。研究了工艺参数和合金成分对两种mpea的效率的影响。结果表明，随着激光功率的增大和扫描速度的降低，两种mpea都出现了明显的CET现象。然而，它们在CET参数、等轴晶粒分数和晶体织构方面存在显著差异。随后，通过有限元模拟研究了工艺参数对温度梯度、凝固速率和熔池形貌的影响，揭示了CoCrNi和feccrni合金晶粒形貌和织构的形成机制。此外，热力学计算结果揭示了两种mpea之间生长限制因子的显著差异，从而解释了两种mpea中观察到的不同的CET行为。

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引用次数: 0