Additive manufacturing letters最新文献

{"title":"Tailoring columnar-to-equiaxed transition in additive manufacturing of Nickel-based superalloys via melt pool control: A theoretical study","authors":"Ting Zhang ,&nbsp;Peiyu Zhang ,&nbsp;Yucong Duan ,&nbsp;Mengxiang Dang ,&nbsp;Wenqian Zhang ,&nbsp;Nuoer Ge","doi":"10.1016/j.addlet.2026.100377","DOIUrl":"10.1016/j.addlet.2026.100377","url":null,"abstract":"<div><div>Tailoring columnar-to-equiaxed transition (CET) in additive manufacturing (AM) or welding of nickel-based superalloys is critical for achieving target mechanical properties. However, maintaining the desired solidification pattern remains challenging due to the highly dynamic nature of the melt pool. This study introduces melt pool features as an intermediate dimension, establishing a “process–melt pool–structure” linkage for real-time monitoring and closed-loop control. Key features such as trailing-point temperature gradient, solidification rate, and width-to-length ratio are defined and correlated with processing parameters using a simple heat-conduction model. The concept of “similar melt pools” is proposed to clarify their effects on solidification conditions. Combined with the classical CET theory, the correlations between melt pool features and final solidification structures are quantified, identifying ranges for stable columnar or equiaxed growth and providing a theoretical basis for solidification control in AM processes.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"17 ","pages":"Article 100377"},"PeriodicalIF":4.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147706362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of TiN nanoparticle on shape memory properties of additively manufactured ferrous high entropy shape memory alloy","authors":"Guoyuan Qiu ,&nbsp;Yaning Tang ,&nbsp;Jianjun Lin ,&nbsp;Jeremy Heng Rao ,&nbsp;Xing Gong ,&nbsp;Changyong Liu ,&nbsp;Zhangwei Chen ,&nbsp;Chao Dong ,&nbsp;Zhiyuan Liu","doi":"10.1016/j.addlet.2026.100356","DOIUrl":"10.1016/j.addlet.2026.100356","url":null,"abstract":"<div><div>Emerging 4D printing is an innovative additive manufacturing (AM) technique that incorporates an extra dimension of time into AM. 4D printed objects can change their shapes or properties in response to external stimuli. However, the intrinsic microstructural anisotropy also affects the shape memory performance of AM printed shape memory alloys (SMAs). This work investigated the effect of TiN nanoparticle addition on the mechanical and shape-memory properties of a high entropy shape memory alloy (HESMA) Fe₅₀Mn₂₀Co₁₀Cr₁₀Si₁₀ (at.%) fabricated by laser powder bed fusion (LPBF). Results show that the TiN addition enhances the yield strength (YS) of the AM HESMA at the expense of ductility. Meanwhile, the as-built shape memory performance is reduced, with the maximum bending recovery strain of the vertical sample decreasing from 6.3 % to 4.7 %. Moreover, it is shown that introducing TiN nanoparticles can significantly alleviate the 4D-printing anisotropy. The YS anisotropy ratio is reduced from 40.0 % to 20.5 %, and the shape memory anisotropy ratio decreases from 56.3 % to 14.9 %. The underlying reason is attributed to a columnar-to-equiaxed microstructure transition induced by the TiN addition, which results in similar amount of grain boundaries during deformation in different directions. To restore the shape memory ability, the TiN/HESMA is subjected to further heat treatment. The maximum recovery strain is improved greatly and approaching that of HESMA matrix, and the shape memory anisotropy ratio further decreases to 3.4 %. The underlying mechanism of the heat treatment is revealed. The synergy of TiN addition and heat treatment provides a novel approach to balance strength enhancement and functional anisotropy of 4D printing</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"17 ","pages":"Article 100356"},"PeriodicalIF":4.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linking process parameters to residual stress and distortion in directed energy deposition repair via machine learning and response surface methodology","authors":"Joachim C.G. Eng ,&nbsp;Louis N.S. Chiu ,&nbsp;Aijun Huang ,&nbsp;Bernard Rolfe ,&nbsp;Wenyi Yan","doi":"10.1016/j.addlet.2026.100370","DOIUrl":"10.1016/j.addlet.2026.100370","url":null,"abstract":"<div><div>Laser-directed energy deposition (L-DED) filling repair is often compromised by printing defects like cracking induced by excessive thermal residual stresses. Optimising process parameters is challenging, as complex thermal histories make trial-and-error costly and simulations computationally inefficient. To bridge this, a finite element (FE)-driven machine learning (ML) framework was developed to optimise multi-layer multi-track filling repair bulk quality. The methodology ensures consistent fill volume by enforcing nominal single-track dimensions. A thermomechanically validated FE model generated training data via design of experiment (DoE) strategies. Among evaluated algorithms, the multilayer perceptron (MLP) achieved superior accuracy (R² = 0.98, NRMSE = 2.7 %) as an efficient surrogate. Integrated response surface methodology (RSM) highlighted a critical trade-off, revealing moderate energy density as the optimal compromise for balancing residual stress and distortion. Furthermore, parameter influence analysis identified scan speed as the dominant control variable, closely followed by laser power and preheat temperature. Ultimately, this framework provides a robust and efficient tool for defining optimal process windows in <span>l</span>-DED filling repair.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"17 ","pages":"Article 100370"},"PeriodicalIF":4.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147384996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting porosity in laser powder bed fusion of metals (PBF-LB/M) using scanning data and machine learning","authors":"Jesus Rivas ,&nbsp;Cesar Terrazas ,&nbsp;Hugo Estrada ,&nbsp;Francisco Medina ,&nbsp;James P. Carney","doi":"10.1016/j.addlet.2026.100362","DOIUrl":"10.1016/j.addlet.2026.100362","url":null,"abstract":"<div><div>Laser powder bed fusion of metals (PBF-LB/M) remains prone to process-induced porosity, and practical tools that connect scan behavior to defect formation are still limited. In this study, we present a framework that predicts porosity from scan data acquired on a commercial PBF-LB/M system using an embedded high-speed scan acquisition device. The device records scanning position, time, and laser power at high temporal resolution, enabling reconstruction of layer-wise exposure paths that are normally inaccessible to users. From these data, we derive porosity-prone “hotspot” regions based on high linear energy input, energy input gradients, and deceleration or acceleration events along the scan path. Ground-truth porosity is obtained from X-ray Computed Tomography (XCT) of a compact qualification artifact containing multiple geometries, including lattice structures. Across the machine learning evaluated models, LSBoost provides the best overall performance when predicting total pore counts per layer with a Mean Absolute Error (MAE) ≈ 7.29. Prediction of larger pores with equivalent diameters greater than 0.100 mm was slightly more accurate (MAE = 4.747), indicating stronger correlation for critical part anomalies. However, porosity outliers tend to be underestimated, highlighting both the need for improved calibration and the benefit of additional in situ process signals that capture interactions with other process variables such as powder or gas flow. Overall, the results demonstrate that scan-derived hotspot features, combined with machine learning, are a viable basis for in situ identification and prediction of porosity-prone layers in PBF-LB/M.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"17 ","pages":"Article 100362"},"PeriodicalIF":4.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring AlSi12 powder size for laser powder bed fusion of multi-materials under oxygenated atmosphere","authors":"Maria Zapata ,&nbsp;Valérie Baco-Carles ,&nbsp;Kateryna Kiryukhina ,&nbsp;Philippe Tailhades","doi":"10.1016/j.addlet.2026.100378","DOIUrl":"10.1016/j.addlet.2026.100378","url":null,"abstract":"<div><div>Although Powder Bed Fusion with Laser Beam (PBF-LB) is increasingly being used to produce functional components, the fabrication of integrated metal–ceramic multi-materials parts remains challenging. This study presents a single-powder PBF-LB strategy enabling the production of AlSi12/alumina multi-materials parts. The ceramic phase is generated in situ through localized oxidation, which is induced by a high surface energy density under oxygen partial pressure. This study aims to evaluate the influence of particle size on the manufacturing of multi-material parts. Two powders with identical composition but with different particle sizes (coarse and fine) were characterized in terms of their physicochemical properties and performance under processing conditions. The coarse powder exhibits the best fluidity and absorbency, indicating superior powder spreading and laser beam absorption. Conversely, the friction forces between particles related to the fine powder lower fluidity, result in increased resistance to ejection during high-energy-density conditions, which are necessary for forming ceramic zones. The results show that both powders can be processed without any chemical pretreatment and that new PBF-LB parameter windows enabling stable in situ oxidation, have been identified. The use of coarse powder improves surface roughness as well as a metal-ceramic interface with less porosity and defects. This highlights the advantages of coarse powder for manufacturing multi-material components. These findings demonstrate the feasibility of producing metal–ceramic architectures using a single aluminum alloy, without prior chemical treatment. The presence of both conductive metal regions and dielectric ceramic zones creates opportunities for the integration of multifunctional components into various advanced applications.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"17 ","pages":"Article 100378"},"PeriodicalIF":4.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147706363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational predictions of complex property trajectories in compositionally graded alloys","authors":"Jixuan Dong ,&nbsp;Hasan Al Jame ,&nbsp;Zachary C. Cordero ,&nbsp;S. Mohadeseh Taheri-Mousavi","doi":"10.1016/j.addlet.2026.100359","DOIUrl":"10.1016/j.addlet.2026.100359","url":null,"abstract":"<div><div>Additive manufacturing enables net-shaped compositionally graded components that satisfy conflicting property requirements through spatial variations in alloy chemistry and microstructure. Although current path-planning methods for compositionally graded alloys emphasize avoiding deleterious phases, property evolution along compositional gradients is equally important because abrupt property changes can degrade structural integrity. In light of this concern, this study integrates high-throughput calculation of phase diagrams (CALPHAD)-based integrated computational materials science (ICME) simulations with variance-based global sensitivity analysis to introduce a framework for designing smoother property transitions. Thermophysical and mechanical properties along binary gradients between pairs of Inconel 718, Monel K-500, and Invar 36 were computed, revealing strongly nonlinear property transitions. Sensitivity analysis identified aluminum as a key driver of variability in thermal expansion coefficient along a transition, and this variability was reduced by tailoring the compositions in the terminal alloys. This framework can be used for similar identification and and tailoring of various property variability to achieve optimal component-level performance.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"17 ","pages":"Article 100359"},"PeriodicalIF":4.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Continuous microstructure variations with graded properties in directed energy deposition","authors":"Michèle Bréhier ,&nbsp;Daniel Weisz-Patrault ,&nbsp;Christophe Tournier","doi":"10.1016/j.addlet.2026.100372","DOIUrl":"10.1016/j.addlet.2026.100372","url":null,"abstract":"<div><div>Directed energy deposition additive manufacturing is a versatile technique for fabricating complex geometries, where precise control of process parameters is crucial for tailoring microstructure and part properties. Microstructure control strategies usually involve variation of material composition (i.e., functionally graded materials) or interlayer time delay. However, the obtained microstructures are usually uniform in the print direction and exhibit sharp transitions from one layer to the next in the build direction. This paper targets continuous microstructural variation by exploiting active cooling strategies to control cooling conditions. To do so, the scanning speed is continuously varied, necessitating accommodating the bead size variations with non-standard trajectory generation based on a phenomenological law. The proposed strategy is demonstrated on thin-wall structures made of IN718 using a powder-based laser directed energy deposition. The results reveal a continuous microstructural transition along the print direction, characterized by two distinct microstructural regimes with markedly different morphological features and crystallographic textures. This demonstrates the capability of scanning speed modulation to engineer heterogeneous microstructures within a single component, offering insights into tailoring material properties for specific engineering applications.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"17 ","pages":"Article 100372"},"PeriodicalIF":4.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “A new approach to laser DED as a repair technology with Laser Mesh Deposition” [Additive Manufacturing Letters, Volume 14, (2025) 100301]","authors":"Thomas Girerd ,&nbsp;Richard Adamson ,&nbsp;Andres Gameros ,&nbsp;Marco Simonelli ,&nbsp;Andy Norton ,&nbsp;Adam Thomas Clare","doi":"10.1016/j.addlet.2026.100358","DOIUrl":"10.1016/j.addlet.2026.100358","url":null,"abstract":"","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"17 ","pages":"Article 100358"},"PeriodicalIF":4.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147740092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Future foundries: A convergent manufacturing platform","authors":"Shramana Ghosh ,&nbsp;Miguel Hoffmann ,&nbsp;Lauren Heinrich ,&nbsp;Kenton B. Fillingim ,&nbsp;Joshua Vaughan ,&nbsp;Brian K. Post ,&nbsp;Thomas Feldhausen","doi":"10.1016/j.addlet.2026.100364","DOIUrl":"10.1016/j.addlet.2026.100364","url":null,"abstract":"<div><div>This article introduces the Future Foundries platform developed at Oak Ridge National Laboratory, a first-generation research system designed to demonstrate convergent manufacturing. Convergent manufacturing brings together additive, subtractive, and transformative processes in a digitally interconnected environment to enable end-to-end production workflows. By linking traditionally discrete steps, convergent platforms accelerate production, improve repeatability, and support high-mix, low-volume manufacturing.</div><div>The Future Foundries platform exemplifies this vision in practice by combining four modular, vendor-agnostic process cells that include robotic WAAM, induction heating, optical metrology, and machining, coordinated through an automated pallet handler and a ROS 2-based digital thread. This architecture provides the flexibility and scalability needed for agile production in small and medium-sized manufacturing enterprises and for field deployable manufacturing.</div><div>Two case studies illustrate the platform’s capabilities. The first presents an integrated workflow for fabricating, transforming, and repairing critical replacement components, showing how consolidated thermal, additive, inspection, and machining operations reduce manual part handling and streamline process flow. The second case study highlights coordinated multi-part production enabled by automated pallet logistics and multi-cell scheduling. Together, these examples showcase convergent manufacturing as a practical and scalable strategy for strengthening domestic casting and forging capacity, improving supply-chain resilience, and enabling rapid, adaptable production of mission-critical components.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"17 ","pages":"Article 100364"},"PeriodicalIF":4.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147384994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Printing multifunctional high-performance polymer parts via the hybridization of high temperature material extrusion thermal and chemical reactive bonding","authors":"Ian Y. Ho ,&nbsp;Jacob Viar ,&nbsp;Hutchison Peter ,&nbsp;Henry Claesson ,&nbsp;Christopher Williams","doi":"10.1016/j.addlet.2026.100367","DOIUrl":"10.1016/j.addlet.2026.100367","url":null,"abstract":"<div><div>Direct fabrication of multifunctional, high-performance components integrating structural dielectric and conductive materials remains a key challenge in advanced manufacturing. Additive manufacturing (AM) enables embedding functional elements layer-by-layer into structural parts. Hybrid material extrusion (MEX) systems have combined thermal reaction bonding (MEX-TRB, or fused filament fabrication, FFF) and chemical reaction bonding (MEX-CRB, or direct ink writing, DIW) modalities within the same system to directly produce multifunctional parts. However, these systems have been limited to depositing conductive traces within commodity polymers (e.g., PLA, ABS, PETG) at ambient conditions to prevent premature ink curing. These polymers lack the thermal stability to withstand high-performance ink sintering temperatures (often &gt;250 °C), limiting conductivity of the dispensed functional inks and resulting applications.</div><div>This work introduces a novel hybrid MEX-CRB/MEX-TRB system with an actively cooled MEX-CRB head to prevent ink curing while operating in chamber temperatures up to 110 °C, enabling the printing of high-performance polymers. In-situ characterization using embedded thermocouples confirmed that the cooling system maintains ink below critical curing thresholds. Conductivity measurements demonstrated successful in-situ sintering and conductive network formation of silver conductive traces within the heated chamber. Polyphenylene sulfide (PPS) parts with embedded silver traces were fabricated, leveraging the chamber for both polymer printing and trace sintering. Compared to traditional hybrid approaches requiring part shuttling between modalities, this integrated system reduces interlayer cooling and improves polymer interlayer adhesion. These results show that the high-temperature hybrid MEX system effectively balances conflicting thermal requirements of high-performance polymers and conductive inks, enabling efficient multimodality printing for advanced electrical applications.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"17 ","pages":"Article 100367"},"PeriodicalIF":4.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147384999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}