Additive manufacturing最新文献

{"title":"An integrated microstructural high strain-rate experimental and computational analysis of the spall behavior of additively manufactured niobium C-103 alloys","authors":"O. Eldaly ,&nbsp;H. Zhang ,&nbsp;T. Virazels ,&nbsp;J.A. Rodríguez-Martínez ,&nbsp;T.J. Horn ,&nbsp;M.A. Zikry","doi":"10.1016/j.addma.2025.104986","DOIUrl":"10.1016/j.addma.2025.104986","url":null,"abstract":"<div><div>Niobium alloys, such as C-103, have been used for high-temperature applications due to their oxidation resistance, high-temperature behavior, and ductility. These characteristics also render C-103 as an attractive material for additive manufacturing (AM) processing. However, there is a lack of fundamental understanding of how defects, such as dislocation density and dislocation density interactions, and texture affect high strain-rate and spall behavior in body-centered cubic (b.c.c.) AM processed C-103 alloys. To address these challenges, electron beam powder bed fusion (EB-PBF) was used to process and fabricate C-103 samples with highly textured columnar grains. Disc-shaped plate-impact test specimens were extracted from the AM-fabricated samples, with the grains oriented either parallel or perpendicular to the build direction, for experiments with loading velocities of up to 600 m/s. The tests were instrumented with a photonic Doppler velocimetry (PDV) system to obtain time-resolved free surface velocity data of the sample and compute the spall strength of C-103 across a wide range of loading rates. These experimental measurements were then integrated with computational predictions based on a dislocation-based crystalline plasticity (DCP) approach coupled with a fracture formulation to understand how defects, such as dislocation densities, affect the spall strength and the defect behavior of C-103. The predictive framework provided insights into how spall cracks nucleate due to a combination of tensile wave reflection and dislocation-density accumulation, and how immobile dislocation accumulation ahead of multiple crack fronts can blunt spall propagation. This interrelated approach provides an understanding of high strain-rate and dynamic fracture of textured AM b.c.c. microstructures that can be tailored to mitigate high-impact velocity and spall in niobium alloys.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"111 ","pages":"Article 104986"},"PeriodicalIF":11.1,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Room-temperature laser crystallization of oxygen vacancy-engineered zirconia for additive manufacturing","authors":"Jaime A. Benavides-Guerrero ,&nbsp;Luis F. Gerlein ,&nbsp;Astrid C. Angel-Ospina ,&nbsp;Paul Fourmont ,&nbsp;Abhiroop Bhattacharya ,&nbsp;Abbas Zirakjou ,&nbsp;Fabrice Vaussenat ,&nbsp;Caroline A. Ross ,&nbsp;Sylvain G. Cloutier","doi":"10.1016/j.addma.2025.104969","DOIUrl":"10.1016/j.addma.2025.104969","url":null,"abstract":"<div><div>We demonstrate how strategically engineered oxygen vacancies enable room-temperature laser crystallization of zirconia (ZrO₂) in ambient air. Our sol-gel chelation synthesis creates amorphous ZrO₂ nanoparticles with a high concentration of oxygen vacancies that fundamentally alter the material's energy landscape. These defects create sub-bandgap states that facilitate visible light absorption and dramatically reduce the energy barrier for crystallization. Under low-energy laser irradiation (405–532 nm), oxygen vacancies mediate a rapid phase transformation mechanism where atmospheric oxygen interacts with vacancy sites, triggering ionic rearrangement and crystallization without conventional high-temperature processing. For comparison purposes, this study also explores the thermal crystallization of black zirconia in an oxidative atmosphere, a process typically performed under vacuum or inert conditions. Through comprehensive characterization (FTIR, EPR, XPS, XRD, Raman), we establish that vacancy-mediated crystallization produces monoclinic ZrO₂ with preserved defect structures, yielding a distinctive black phase with 25.6 % oxygen vacancy concentration, significantly higher than thermally processed counterparts (9.2 %). This vacancy-enabled crystallization circumvents the need for extreme temperatures (&gt;1170°C) typically required for ZrO₂ processing, making it compatible with additive manufacturing. Using a modified 3D printer with a 405 nm laser, we demonstrate patterned crystallization of complex architectures, opening new possibilities for fabricating advanced ZrO₂-based devices for photocatalysis, fuel cells, and energy applications. This work provides fundamental insights into defect-mediated phase transformations and establishes a new paradigm for room-temperature ceramic processing.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"111 ","pages":"Article 104969"},"PeriodicalIF":11.1,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145107675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress-induced martensitic transformation mechanism in the crack behaviour of compressed additively manufactured Ti-5553 alloy: A variant selection approach","authors":"Carlos Samuel Alves da Silva ,&nbsp;Hugo Magalhães de Azevedo ,&nbsp;Matheus Valentim ,&nbsp;Gilberto Vicente Prandi ,&nbsp;João Felipe Queiroz Rodrigues ,&nbsp;Kaio Niitsu Campo ,&nbsp;Hamilton Ferreira Gomes de Abreu ,&nbsp;Rubens Caram","doi":"10.1016/j.addma.2025.104954","DOIUrl":"10.1016/j.addma.2025.104954","url":null,"abstract":"<div><div>This investigation aims to explore the unresolved crack formation mechanism in compression, based on the influence of the crystallographic nature in the Ti-5553 alloy, which is susceptible to Laser Powder Bed Fusion (PBF-LB) defects as well as stress-induced martensitic transformations (SIMT). The cylindrical samples were obtained and subsequently subjected to a compressive load to investigate the BCC/orthorhombic transformation in the failure behaviour. Here, the variant selection approach based on the Schmid factor (SF) criteria was employed to elucidate the martensitic phase transformations and their role in the crack path. It was demonstrated that the accumulation of plastic strain at discontinuities that result from the processing route initiate the martensitic transformation. Additionally, a stacking fault in the orthorhombic phase will assist the α’’/α’ (Orthorhombic/Hexagonal closed packed - HCP) transformation. The analysis showed that the SIMT mechanism follows the <span><math><msub><mrow><mo>{</mo><mn>101</mn><mo>}</mo></mrow><mrow><mi>β</mi></mrow></msub></math></span>//<span><math><msub><mrow><mo>{</mo><mn>001</mn><mo>}</mo></mrow><mrow><mi>α</mi><mo>′</mo><mo>′</mo></mrow></msub></math></span>//<span><math><msub><mrow><mo>{</mo><mn>0001</mn><mo>}</mo></mrow><mrow><mi>α</mi><mo>′</mo></mrow></msub></math></span> and <span><math><msub><mrow><mo>&lt;</mo><mn>111</mn><mo>&gt;</mo></mrow><mrow><mi>β</mi></mrow></msub></math></span>//<span><math><msub><mrow><mo>&lt;</mo><mn>110</mn><mo>&gt;</mo></mrow><mrow><mi>α</mi><mo>′</mo><mo>′</mo></mrow></msub></math></span>//<span><math><msub><mrow><mo>&lt;</mo><mn>11</mn><mover><mrow><mn>2</mn></mrow><mo>̅</mo></mover><mn>0</mn><mo>&gt;</mo></mrow><mrow><mi>α</mi><mo>′</mo></mrow></msub></math></span> orientation relationship and that the failure on the transverse direction follows a direction close to <span><math><msub><mrow><mo>&lt;</mo><mn>212</mn><mo>&gt;</mo></mrow><mrow><mi>β</mi></mrow></msub></math></span> // <span><math><msub><mrow><mo>&lt;</mo><mn>211</mn><mo>&gt;</mo></mrow><mrow><mi>α</mi><mo>′</mo><mo>′</mo></mrow></msub></math></span>//TD.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"111 ","pages":"Article 104954"},"PeriodicalIF":11.1,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ceramic insert enabled build plate thermal isolation for enhanced microstructure and residual stress mitigation in laser-based powder bed fusion of metals","authors":"Soung Yeoul Ahn ,&nbsp;Sang Guk Jeong ,&nbsp;Gitaek Lee ,&nbsp;Hobyung Chae ,&nbsp;Wanchuck Woo ,&nbsp;Eun Seong Kim ,&nbsp;Muhammad Raihan Hashmi ,&nbsp;Levin Sebastian Cahyaputra ,&nbsp;Renhao Wu ,&nbsp;Sun Ig Hong ,&nbsp;Soon-Jik Hong ,&nbsp;Hyoung Seop Kim","doi":"10.1016/j.addma.2025.104967","DOIUrl":"10.1016/j.addma.2025.104967","url":null,"abstract":"<div><div>Mitigating thermally induced residual stresses remains a critical challenge in components made by laser-based powder bed fusion of metals (PBF-LB/M). This study proposes a novel passive thermal isolation strategy utilizing a ceramic base plate to control thermal gradients during fabrication, which in turn reduces residual stress and simultaneously inducing distinct microstructural differences in PBF-LB/M processed stainless steel 316 L alloys. A combined approach using finite element method (FEM) simulations, neutron diffraction, microstructure analysis, and mechanical testing, was employed to systematically evaluate the thermal, structural, and mechanical responses. The ceramic base plate elevates the temperatures of the part during fabrication while reducing thermal gradients, and effect that corresponded with neutron diffraction measurements showing reduced tensile and compressive residual stresses across the build. Importantly, distinct microstructure differences were identified, characterized by grain coarsening, reduced local misorientation, a lower twin fractions, and diminished defects. Collectively, these features promoted greater microstructural uniformity and effectively suppressed thermal induced plasticity. The enhanced microstructural homogeneity across different locations also contributed to more uniform mechanical properties throughout the specimen. Unlike conventional strategies requiring additional energy input or system modifications, the proposed approach offers a scalable, energy-efficient, and easily implementable solution that does not interfere with existing machine control systems. It can be integrated with other stress-relief methods such as preheating, and/or other active systems to provide synergistic effects. Moreover, the reduced thermal deformation enhances dimensional accuracy and manufacturing reliability, without compromising mechanical performance, addressing critical requirements in aerospace, biomedical, and energy applications.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"111 ","pages":"Article 104967"},"PeriodicalIF":11.1,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revealing the interplay between element mixing, intermetallics, and microcracks in multi-material laser additive manufacturing","authors":"Jingyu Xu ,&nbsp;Dongxu Cheng ,&nbsp;Xuxiao Li ,&nbsp;Heng Gu ,&nbsp;Wei Li ,&nbsp;Chenxi Lu ,&nbsp;Xiao Yang ,&nbsp;Lin Li ,&nbsp;Chao Wei","doi":"10.1016/j.addma.2025.104971","DOIUrl":"10.1016/j.addma.2025.104971","url":null,"abstract":"<div><div>Additive manufacturing (AM) of multiple metallic materials suffers from microcracks at the dissimilar material interface due to brittle intermetallic compounds (IMCs). While avoiding IMCs through specialized composition design is a conventional approach, the interdependence between molten pool material mixing, IMC characteristics, and microcracks are not well understood. In this work, we compared typical process conditions for laser powder bed fusion of aluminum alloy substrate and Inconel particles. We revealed that the insufficient dissimilar material mixing under the lower energy density condition can exacerbate element clustering, IMC concentration, and cracking. High-speed synchrotron X-ray imaging shows that Ni-rich clusters can abruptly plunge into the molten pool to cause localization of IMCs and microcracks. In the high energy density case, the keyhole oscillation can disperse the Ni-rich clusters and suppress cracks but lead to keyhole porosities. Microstructural characterization and multiphysics simulations support the X-ray imaging observations. We propose that control of molten pool flow to enhance mixing while preventing porosities is the key to crack-free AM of metallurgically incompatible dual alloys.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"111 ","pages":"Article 104971"},"PeriodicalIF":11.1,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fractured rock analogs by binder jetting 3D printing using cement: Improvements in geometric similarity and mechanical performance","authors":"Zhuo Cheng ,&nbsp;Yaoyu Zhang ,&nbsp;Tingyu Hu ,&nbsp;Zhijian Li ,&nbsp;Guowei Ma","doi":"10.1016/j.addma.2025.104976","DOIUrl":"10.1016/j.addma.2025.104976","url":null,"abstract":"<div><div>Reliable evaluation of the mechanical contribution of fracture networks and deformation parameters of rock matrices is a prerequisite for stability analysis for the safe operation of practical geomechanical engineering projects. Current research for evaluation is underscored by three-dimensional (3D) cementitious printing, particularly binder jetting, to reproduce fracture networks with high fidelity in geometries and deformation/strength parameters of the matrix to those of their natural counterparts. Nevertheless, it has been argued that current 3D printing techniques are inadequate in terms of precision in capturing the geometric features of fractures, and the strength of the printed matrix is generally lower than that of some natural hard rock matrices. To this end, this study developed a 3D binder-jetting cementitious printing methodology with high precision for constructing a fractured rock analog. 3D fractures were fabricated by extracting practical fracture network geometries from scanned computed tomography (CT) images, demonstrating less than 5 % error in key geometric parameters, including the maximum inclination angle, maximum area, porosity, and fractal dimension. High printing precision and mechanical properties of the printed samples were achieved by optimizing the printing parameters and dry-heat curing process. The accuracy of the printed internal fractures was evaluated using CT and dimensional measurements. The mechanical properties of the specimens were tested using uniaxial compression and Brazilian splitting experiments. The microscopic compositions and microstructures of the specimens were obtained using scanning electron microscopy, X-ray diffraction, and thermal analysis techniques. The test results showed that optimizing the binder saturation can significantly improve the dimensional accuracy and effectively reduce the mechanical anisotropy. Dry heat curing enhances both geometric accuracy and mechanical performance by accelerating hydration and restraining binder diffusion. Specimens cured at 40 °C for 3 d yields significantly improved dimensional accuracy and a 40 %–60 % increase in mechanical properties compared to those without thermal curing. These specimens closely approximated natural sandstone with respect to compressive strength, elastic modulus, splitting strength, brittleness index, and failure patterns. The experimental results demonstrate the effectiveness of the proposed CT data-based binder jetting 3D printing methodology in reliably replicating complex fractured rock geometries and mechanics.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"111 ","pages":"Article 104976"},"PeriodicalIF":11.1,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Creep of direct-energy-deposited Inconel 625 with evolving microstructure","authors":"Tiffany Wu ,&nbsp;KenHee Ryou ,&nbsp;Rujing Zha ,&nbsp;Rowan Rolark ,&nbsp;Jian Cao ,&nbsp;David C. Dunand","doi":"10.1016/j.addma.2025.104979","DOIUrl":"10.1016/j.addma.2025.104979","url":null,"abstract":"<div><div>Microstructure and compressive creep properties at 750–850˚C are investigated for an Inconel 625 superalloy fabricated via direct energy deposition of powders. The effects of solution treatment, test temperature, and loading direction on secondary creep rate are studied using conventional stress-jump tests, with additional stress-drop tests conducted to shed light on the effect of stress history on primary creep. After creep, as-fabricated samples maintain their columnar grains, whereas hot isostatic pressed (HIPed) samples undergo dynamic recrystallization, resulting in coarser equiaxed grains containing annealing twins. Despite the difference in microstructure, as-fabricated and HIPed samples have comparable creep resistance with a stress exponent of 6 and 5, respectively. Within HIPed samples, the stress exponent increases from 5 to 8 as the temperature decreases from 850 to 750˚C due to the denser distribution of fine δ phases (rods with lengths of a few hundred nm) formed within grains at lower temperatures (800 and 750˚C). Regardless of the creep temperature, duration, and stress history (stress-jump/ -drop), a fully recrystallized grain structure is observed in all HIPed samples. In addition, the strain accumulated during primary creep is higher for the first loading than the later stress jumps/drops, indicative of dynamic recrystallization prolonging the primary creep stage. Samples undergoing stress-drop tests show a shorter primary creep regime with less strain accumulated. Lastly, Andrade law applies for the primary creep strain at later stress jumps/drops, with a stress-dependent prefactor.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"111 ","pages":"Article 104979"},"PeriodicalIF":11.1,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microstructure characteristics of LPBF&HIP fabricated graded composite transition joint between ferritic steel and austenitic stainless steel","authors":"Yuying Wen ,&nbsp;Shanshan Hu ,&nbsp;Youyuan Zhang ,&nbsp;Ting Sun ,&nbsp;Luke Wadle ,&nbsp;Lanh Trinh ,&nbsp;Xingru Tan ,&nbsp;Susheng Tan ,&nbsp;Wei Zhang ,&nbsp;Haiyang Qian ,&nbsp;Bai Cui ,&nbsp;Yanli Wang ,&nbsp;Zhili Feng ,&nbsp;Xingbo Liu","doi":"10.1016/j.addma.2025.104961","DOIUrl":"10.1016/j.addma.2025.104961","url":null,"abstract":"<div><div>Graded composite transition joints (GCTJs) offer a promising alternative to conventional dissimilar metal welds (DMWs) by enabling smooth compositional and microstructural transitions. However, GCTJs fabricated solely through additive manufacturing (AM) face challenges such as heat accumulation, complex parameter control, and elemental segregation. In this study, we propose a novel approach that relies on AM to design a spatially graded structure in one alloy and then employs hot isostatic pressing (HIP) as a diffusion bonding method to join it with a second alloy. This method combines the flexibility of AM with the powder net-shaping advantage of HIP. Specifically, a series of closely packed austenitic stainless steel 304 conical structures were printed using laser powder bed fusion (LPBF) and then combined with ferritic steel P91 powder via HIP. By using electron backscatter diffraction (EBSD), electron probe microanalysis (EPMA), and transmission electron microscopy (TEM) techniques, the microstructure characteristics of the GCTJ of 304&amp;P91, especially the interdiffusion zone (IDZ), have been systematically investigated. The microstructure at the interface transitions from austenite-ferrite (A+F) to austenite-martensite-ferrite (A+M+F), and finally to martensite-ferrite (M+F) due to diffusion. Additionally, the diffusion width between 304 and P91 increases with the volume fraction of P91. This unique design also ensures a gradual transition in both hardness and thermal expansion coefficient from 304 to P91, thereby enabling a smooth gradient in functional properties. Overall, this study proposes a novel approach for fabricating GCTJs and contributes to advancing design concepts in the field of dissimilar metal joining.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"111 ","pages":"Article 104961"},"PeriodicalIF":11.1,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microscale additively manufactured 3D metal-ceramic nanocomposites with improved strength and thermal stability","authors":"Nadia Rohbeck ,&nbsp;Maria Watroba ,&nbsp;Christopher Gunderson ,&nbsp;Alexander Groetsch ,&nbsp;Manish Jain ,&nbsp;Janne-Petteri Niemelä ,&nbsp;Aurelio Borzi ,&nbsp;Ivo Utke ,&nbsp;Xavier Maeder ,&nbsp;Antonia Neels ,&nbsp;Johann Michler ,&nbsp;Jakob Schwiedrzik","doi":"10.1016/j.addma.2025.104957","DOIUrl":"10.1016/j.addma.2025.104957","url":null,"abstract":"<div><div>Nanocomposites hold great promise for enhancing material properties beyond those of conventional materials. Here, we present a novel method integrating template-assisted electrodeposition of nanocrystalline gold (nc Au) and atomic layer deposition (ALD) of alumina to fabricate three-dimensional nanostructured metal matrix composites (MMCs) with enhanced mechanical strength, reduced density, and improved thermal stability. Microcompression experiments demonstrate that Au-alumina MMC achieves a yield strength of 838 MPa, outperforming pure nc Au (792 MPa) and Au hollow microlattices (250 MPa). The strength advantage increases at elevated temperatures: the MMC exhibits a 5 % improvement in yield strength at room temperature while retaining only 80 % of the weight, rising to a 42 % improvement at 100 °C. To enable design and optimization of such nanocomposites, we performed a systematic thermomechanical study on pure nc Au. Compression tests across a range of temperatures (23 °C to 100 °C) and strain rates (0.0004 s⁻¹ to 216 s⁻¹) revealed a transition in deformation behavior around 1 s⁻¹ . In the quasistatic regime, strain rate sensitivity increased from 0.025 to 0.063 with temperature, while remaining low (0.013) and temperature-independent at higher strain rates. The increase in activation volume (10 b³ to 24 b³) and activation energy (49–83 kJ/mol) with strain rate suggests a change in the rate-controlling mechanism. These results provide essential input for finite element modeling (FEM) of MMC, enabling identification of architectural parameters that can be tuned to optimize strength before fabrication. This work demonstrates the potential of microscale additive manufacturing and hybrid fabrication strategies to produce nanocomposites with tunable thermomechanical properties for demanding structural applications.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"111 ","pages":"Article 104957"},"PeriodicalIF":11.1,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of critical flaw sizes and crack driving forces during additive manufacturing of metallic materials","authors":"Kaitlyn M. Mullin ,&nbsp;Tresa M. Pollock ,&nbsp;Matthew R. Begley","doi":"10.1016/j.addma.2025.104985","DOIUrl":"10.1016/j.addma.2025.104985","url":null,"abstract":"<div><div>Additive manufacturing (AM) of complex engineering components is often plagued by a high susceptibility to cracking, particularly in high-strength metallic materials. While alloy design efforts have made progress in mitigating solidification defects, there remains a need for mechanistic guidelines to predict susceptibility to solid-state cracking. To address this gap, driving forces for the growth of melt pool cracks are calculated across a wide range of alloys using an efficient computational framework. Calculations are coupled with rapid single track laser experiments to elucidate trends in cracking from laser melting. The analyses conducted here highlight the important role of material properties in susceptibility to cracking, notably fracture toughness and elastic modulus. An important finding is that residual stresses that are limited in magnitude to the yield stress of the material are likely insufficient to drive cracking during cooling. The implications of these results are discussed in the context of alloy design for AM and residual stress accumulation during AM.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"111 ","pages":"Article 104985"},"PeriodicalIF":11.1,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}