Additive manufacturing最新文献_第4页

Evolving stress-guided continuous fiber path optimization for multi-axis additive manufacturing of composite shells 复合材料壳体多轴增材制造中应力导向连续纤维路径的演化优化

IF 11.1 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-09-05 DOI: 10.1016/j.addma.2025.105012

Yuexin Yang , Ziyi Xu , Molong Duan

Continuous fiber-reinforced polymer composites exhibit superior mechanical properties critical for engineering applications demanding high strength-to-weight ratios. Additive manufacturing enables customized fiber placement and fabrication of complex geometries, particularly for shell structures. Existing research mostly exploits the stress fields in homogeneous components and optimizes fiber layouts by aligning the fibers with the principal stress fields. However, fiber incorporation substantially alters stress distribution, potentially resulting in suboptimal fiber path design without considering the evolution of stress fields across successive layers. Additionally, existing methodologies typically formulate the fiber optimization as a direct 3D problem, thereby encountering significant challenges when simultaneously addressing spatial fiber layouts, stress field considerations, fiber reinforcement effects, and manufacturing constraints. This work presents a novel, efficient framework for the design and manufacturing of mechanically optimized multi-layer composite shells through fiber path optimization strategies. The 3D shell surface is initially mapped to a 2D domain using modified quasi-conformal mapping, with a derived semi-analytical relationship characterizing distortion and expansion. Within the 2D domain, the component's stress field is computed iteratively, and the evolving stress distributions guide a multi-objective optimization incorporating density-controllable path extraction algorithms to generate continuous fiber paths. Furthermore, a constrained one-stroke toolpath generation algorithm is formulated to address manufacturing limitations while ensuring fiber continuity. Apart from the effectiveness of the proposed method shown by simulation results, experimental validation through multi-axis additive manufacturing confirms that optimized structures achieve enhanced structural stiffness and increased peak load capacity compared to conventional constant spacing and orientation fiber patterns, as well as existing stress-guided fiber optimization approaches.

连续纤维增强聚合物复合材料具有优异的机械性能，对于要求高强度重量比的工程应用至关重要。增材制造可以定制纤维布局和复杂几何形状的制造，特别是对于外壳结构。现有的研究大多是利用均匀构件的应力场，通过将纤维与主应力场对齐来优化纤维布局。然而，纤维掺入大大改变了应力分布，如果不考虑连续层应力场的演变，可能导致光纤路径设计不理想。此外，现有的方法通常将纤维优化作为一个直接的3D问题，因此在同时解决空间纤维布局、应力场考虑、纤维增强效应和制造限制时遇到了重大挑战。本文通过纤维路径优化策略，为多层复合材料壳体的机械优化设计和制造提供了一种新颖、高效的框架。利用改进的拟保角映射将三维壳体表面初始映射到二维区域，并推导出表征变形和展开的半解析关系。在二维区域内，迭代计算组件的应力场，并根据不断变化的应力分布指导结合密度可控路径提取算法的多目标优化，以生成连续的光纤路径。此外，制定了一种约束的一冲程刀具轨迹生成算法，以解决制造限制，同时确保纤维的连续性。除了仿真结果表明该方法的有效性外，通过多轴增材制造的实验验证证实，与传统的等间距和取向纤维模式以及现有的应力导向纤维优化方法相比，优化后的结构获得了更高的结构刚度和峰值载荷能力。

{"title":"Evolving stress-guided continuous fiber path optimization for multi-axis additive manufacturing of composite shells","authors":"Yuexin Yang , Ziyi Xu , Molong Duan","doi":"10.1016/j.addma.2025.105012","DOIUrl":"10.1016/j.addma.2025.105012","url":null,"abstract":"<div><div>Continuous fiber-reinforced polymer composites exhibit superior mechanical properties critical for engineering applications demanding high strength-to-weight ratios. Additive manufacturing enables customized fiber placement and fabrication of complex geometries, particularly for shell structures. Existing research mostly exploits the stress fields in homogeneous components and optimizes fiber layouts by aligning the fibers with the principal stress fields. However, fiber incorporation substantially alters stress distribution, potentially resulting in suboptimal fiber path design without considering the evolution of stress fields across successive layers. Additionally, existing methodologies typically formulate the fiber optimization as a direct 3D problem, thereby encountering significant challenges when simultaneously addressing spatial fiber layouts, stress field considerations, fiber reinforcement effects, and manufacturing constraints. This work presents a novel, efficient framework for the design and manufacturing of mechanically optimized multi-layer composite shells through fiber path optimization strategies. The 3D shell surface is initially mapped to a 2D domain using modified quasi-conformal mapping, with a derived semi-analytical relationship characterizing distortion and expansion. Within the 2D domain, the component's stress field is computed iteratively, and the evolving stress distributions guide a multi-objective optimization incorporating density-controllable path extraction algorithms to generate continuous fiber paths. Furthermore, a constrained one-stroke toolpath generation algorithm is formulated to address manufacturing limitations while ensuring fiber continuity. Apart from the effectiveness of the proposed method shown by simulation results, experimental validation through multi-axis additive manufacturing confirms that optimized structures achieve enhanced structural stiffness and increased peak load capacity compared to conventional constant spacing and orientation fiber patterns, as well as existing stress-guided fiber optimization approaches.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"113 ","pages":"Article 105012"},"PeriodicalIF":11.1,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145518218","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}

引用次数: 0

Fast-response machine learning surrogate model of spatter transport in a laser powder bed fusion machine 激光粉末床熔样机飞溅输运的快速响应机器学习代理模型

IF 11.1 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-09-05 DOI: 10.1016/j.addma.2025.105013

Nicholas O’Brien, Satbir Singh, Jack Beuth

In laser powder bed fusion (L-PBF), it is still difficult to produce defect-free parts. Spatter particles are one cause of lack-of-fusion (LOF) defects, which develop when spatter particles land on a part and become incorporated into the melt-pool. Preventing spatter-induced defects could thus be possible by planning for spatter contamination in the build planning phase. Several prior works have shown the promise of using computational fluid dynamics coupled with the discrete phase method (CFD-DPM) to predict the landing locations of spatter particles, but these models are too slow and complex for practical use in build planning. The current work thus proposes a machine learning surrogate model of a CFD-DPM model which performs hundreds of times faster than the original model with a root-mean-square error (RMSE) of 6.8 mm. This model is trained on Inconel 718 spatter particles within the EOS M290 L-PBF machine, but the approach is general and could be extended to other materials and L-PBF machines with retraining of the surrogate model. The model’s learned feature importance is evaluated through a SHAP analysis, finding that it follows previous analyses conducted with the original CFD-DPM model. The model’s accuracy and speed open the possibility for interactively and automatically planning builds around spatter contamination, both of which would improve consistency among machine users and could help reduce the amount of spatter contamination during L-PBF builds.

在激光粉末床熔化（L-PBF）中，制造无缺陷零件仍然是一个难题。飞溅颗粒是导致熔合不足（LOF）缺陷的原因之一，当飞溅颗粒落在零件上并融入熔池时，就会产生熔合不足（LOF）缺陷。因此，通过在构建计划阶段对飞溅污染进行规划，可以防止飞溅引起的缺陷。先前的一些研究表明，利用计算流体动力学和离散相方法（CFD-DPM）来预测飞溅粒子的着陆位置是有希望的，但这些模型太慢，太复杂，无法在建筑规划中实际使用。因此，目前的工作提出了一种CFD-DPM模型的机器学习代理模型，该模型的执行速度比原始模型快数百倍，均方根误差（RMSE）为6.8 mm。该模型在EOS M290 L-PBF机器中的Inconel 718飞溅颗粒上进行训练，但该方法是通用的，可以通过代理模型的再训练扩展到其他材料和L-PBF机器。通过SHAP分析评估模型的学习特征重要性，发现它遵循先前使用原始CFD-DPM模型进行的分析。该模型的准确性和速度为围绕飞溅污染进行交互式和自动规划构建提供了可能，这两者都将提高机器用户之间的一致性，并有助于减少L-PBF构建期间的飞溅污染量。

{"title":"Fast-response machine learning surrogate model of spatter transport in a laser powder bed fusion machine","authors":"Nicholas O’Brien, Satbir Singh, Jack Beuth","doi":"10.1016/j.addma.2025.105013","DOIUrl":"10.1016/j.addma.2025.105013","url":null,"abstract":"<div><div>In laser powder bed fusion (L-PBF), it is still difficult to produce defect-free parts. Spatter particles are one cause of lack-of-fusion (LOF) defects, which develop when spatter particles land on a part and become incorporated into the melt-pool. Preventing spatter-induced defects could thus be possible by planning for spatter contamination in the build planning phase. Several prior works have shown the promise of using computational fluid dynamics coupled with the discrete phase method (CFD-DPM) to predict the landing locations of spatter particles, but these models are too slow and complex for practical use in build planning. The current work thus proposes a machine learning surrogate model of a CFD-DPM model which performs hundreds of times faster than the original model with a root-mean-square error (RMSE) of 6.8mm. This model is trained on Inconel 718 spatter particles within the EOS M290 L-PBF machine, but the approach is general and could be extended to other materials and L-PBF machines with retraining of the surrogate model. The model’s learned feature importance is evaluated through a SHAP analysis, finding that it follows previous analyses conducted with the original CFD-DPM model. The model’s accuracy and speed open the possibility for interactively and automatically planning builds around spatter contamination, both of which would improve consistency among machine users and could help reduce the amount of spatter contamination during L-PBF builds.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"113 ","pages":"Article 105013"},"PeriodicalIF":11.1,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145465216","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}

引用次数: 0

Synergistic control mechanism of thermal vibration stress relief on residual stress and mechanical properties of additively manufactured AlSi10Mg 热振动应力消除对增材制造AlSi10Mg残余应力和力学性能的协同控制机理

IF 11.1 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-09-05 DOI: 10.1016/j.addma.2025.105018

Zhiying Gao , Hechuan Song , Qingdong Zhang , Boyang Zhang

During the manufacture of AlSi10Mg alloys by laser selective melting (SLM), residual stresses due to temperature gradients severely affect the service performance of the parts. Thermal vibration stress relief (TVSR), as a new aging method, can relieve residual stresses and improve mechanical properties efficiently and rapidly. However, the control effect of this method on the residual stress and mechanical properties of SLM-AlSi10Mg alloys is not yet clear. For this, vibrational stress relief (VSR), thermal stress relief for 2 h (TSR-2h), TSR-8h, and TVSR methods were applied to treat the SLM-AlSi10Mg samples, respectively. The results showed that the VSR treatment promoted micro-strain and increased the dislocation density through the superposition of dynamic and residual stresses, with a residual stress relief rate of 34.33 %. The TSR-2h treatment increased the thermal activation energy and promoted the precipitation of the nano-Si phase with a residual stress relief of 48.51 %. TVSR increases the residual stress relief to 65.52 % by the synergistic effect of both. Due to the important role of dislocations in residual stress relief, a dislocation density evolution model was developed to reveal the relationship between the dynamic evolution of dislocations and residual stress in TVSR treatment. Furthermore, the yield strength of the TVSR-treated samples was enhanced by 16.58 %, which was attributed to the precipitation and dislocation strengthening mechanisms. The strengthening model was developed to quantitatively reveal the contribution of multiple strengthening mechanisms to the yield strength of the samples before and after aging.

在AlSi10Mg合金激光选择性熔化（SLM）过程中，由于温度梯度产生的残余应力严重影响了零件的使用性能。热振动应力消除（TVSR）作为一种新型的时效方法，能够有效、快速地消除残余应力，提高材料的力学性能。然而，该方法对SLM-AlSi10Mg合金残余应力和力学性能的控制效果尚不清楚。为此，分别采用振动应力消除（VSR）、2 h热应力消除（TSR-2h）、TSR-8h和TVSR方法处理SLM-AlSi10Mg样品。结果表明：VSR处理通过动应力和残余应力的叠加，促进了微应变的产生，增加了位错密度，残余应力消除率为34.33 %；TSR-2h处理提高了热活化能，促进了纳米si相的析出，残余应力消除率为48.51% %。在两者的协同作用下，TVSR将残余应力消除率提高到65.52 %。鉴于位错在残余应力消除中的重要作用，建立了位错密度演化模型，揭示了在TVSR处理过程中位错动态演化与残余应力之间的关系。此外，tsr处理后的试样屈服强度提高了16.58 %，这归因于析出和位错强化机制。为了定量揭示多种强化机制对时效前后试样屈服强度的贡献，建立了强化模型。

{"title":"Synergistic control mechanism of thermal vibration stress relief on residual stress and mechanical properties of additively manufactured AlSi10Mg","authors":"Zhiying Gao , Hechuan Song , Qingdong Zhang , Boyang Zhang","doi":"10.1016/j.addma.2025.105018","DOIUrl":"10.1016/j.addma.2025.105018","url":null,"abstract":"<div><div>During the manufacture of AlSi10Mg alloys by laser selective melting (SLM), residual stresses due to temperature gradients severely affect the service performance of the parts. Thermal vibration stress relief (TVSR), as a new aging method, can relieve residual stresses and improve mechanical properties efficiently and rapidly. However, the control effect of this method on the residual stress and mechanical properties of SLM-AlSi10Mg alloys is not yet clear. For this, vibrational stress relief (VSR), thermal stress relief for 2 h (TSR-2h), TSR-8h, and TVSR methods were applied to treat the SLM-AlSi10Mg samples, respectively. The results showed that the VSR treatment promoted micro-strain and increased the dislocation density through the superposition of dynamic and residual stresses, with a residual stress relief rate of 34.33 %. The TSR-2h treatment increased the thermal activation energy and promoted the precipitation of the nano-Si phase with a residual stress relief of 48.51 %. TVSR increases the residual stress relief to 65.52 % by the synergistic effect of both. Due to the important role of dislocations in residual stress relief, a dislocation density evolution model was developed to reveal the relationship between the dynamic evolution of dislocations and residual stress in TVSR treatment. Furthermore, the yield strength of the TVSR-treated samples was enhanced by 16.58 %, which was attributed to the precipitation and dislocation strengthening mechanisms. The strengthening model was developed to quantitatively reveal the contribution of multiple strengthening mechanisms to the yield strength of the samples before and after aging.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"113 ","pages":"Article 105018"},"PeriodicalIF":11.1,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145518281","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}

引用次数: 0

Inhomogeneities in directed energy deposition of refractory metals with widely different melting temperatures and mass densities 熔融温度和质量密度大不相同的难熔金属定向能沉积中的不均匀性

IF 11.1 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-09-05 DOI: 10.1016/j.addma.2025.104989

A.J. Stair , Alexander J. Myers , Jonathan A. Malen , Bryan A. Webler , Jack L. Beuth , Maarten P. de Boer

Laser beam directed energy deposition (DED-LB) is of interest as a manufacturing method for refractory complex concentrated alloys. However, in-situ mixing of metals with large differences in melting temperature and density can lead to inhomogeneities, which in turn can give rise to locally varying physical properties. To gain insight into these issues, we investigate the deposition of refractory metal Nb and Ta powders on like and unlike baseplates. The melting temperatures of Ta and Nb differ by 550 °C, while the density of Ta is twice that of Nb. When Ta powder is deposited on a Nb baseplate, un-melted Ta powder particles are observed. Bands of different compositions are also observed throughout the melt pools, both when Ta powder is deposited on Nb baseplate and when Nb powder is deposited on Ta baseplate. Deposition of the denser Ta atop a Nb baseplate results in a chaotic interface profile, while the interface is smooth in the opposite case. In autogenous melt pools, the grain sizes are about 10 times larger than those of the pure baseplates. However, the average melt pool hardnesses are larger by 6 % and 32 % than those of the Ta and Nb baseplates, respectively. The hardness increase is attributed to work hardening. This work provides a systematic study on process parameter dependence of inhomogeneities in DED-LB melt pools when physical properties of materials to be combined are significantly different.

激光定向能沉积（d - lb）是一种制备难熔复杂浓缩合金的新方法。然而，熔融温度和密度差异很大的金属的原位混合会导致不均匀性，从而导致局部物理性质的变化。为了深入了解这些问题，我们研究了难熔金属Nb和Ta粉末在类基板和异类基板上的沉积。Ta和Nb的熔化温度相差550℃，而Ta的密度是Nb的两倍。当Ta粉沉积在Nb基板上时，观察到未熔化的Ta粉颗粒。当Ta粉末沉积在Nb基板上和Nb粉末沉积在Ta基板上时，在整个熔池中也观察到不同成分的条带。致密的Ta沉积在Nb基板上导致界面轮廓混乱，而相反情况下界面光滑。在自生熔池中，颗粒尺寸比纯底板大10倍左右。然而，平均熔池硬度分别比Ta和Nb基板高6 %和32 %。硬度增加是由于加工硬化。本文系统地研究了当待组合材料的物理性质显著不同时，d - lb熔池中不均匀性对工艺参数的依赖关系。

{"title":"Inhomogeneities in directed energy deposition of refractory metals with widely different melting temperatures and mass densities","authors":"A.J. Stair , Alexander J. Myers , Jonathan A. Malen , Bryan A. Webler , Jack L. Beuth , Maarten P. de Boer","doi":"10.1016/j.addma.2025.104989","DOIUrl":"10.1016/j.addma.2025.104989","url":null,"abstract":"<div><div>Laser beam directed energy deposition (DED-LB) is of interest as a manufacturing method for refractory complex concentrated alloys. However, in-situ mixing of metals with large differences in melting temperature and density can lead to inhomogeneities, which in turn can give rise to locally varying physical properties. To gain insight into these issues, we investigate the deposition of refractory metal Nb and Ta powders on like and unlike baseplates. The melting temperatures of Ta and Nb differ by 550 °C, while the density of Ta is twice that of Nb. When Ta powder is deposited on a Nb baseplate, un-melted Ta powder particles are observed. Bands of different compositions are also observed throughout the melt pools, both when Ta powder is deposited on Nb baseplate and when Nb powder is deposited on Ta baseplate. Deposition of the denser Ta atop a Nb baseplate results in a chaotic interface profile, while the interface is smooth in the opposite case. In autogenous melt pools, the grain sizes are about 10 times larger than those of the pure baseplates. However, the average melt pool hardnesses are larger by 6 % and 32 % than those of the Ta and Nb baseplates, respectively. The hardness increase is attributed to work hardening. This work provides a systematic study on process parameter dependence of inhomogeneities in DED-LB melt pools when physical properties of materials to be combined are significantly different.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"113 ","pages":"Article 104989"},"PeriodicalIF":11.1,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145428819","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}

引用次数: 0

Process mapping of Ti-6Al-4V laser powder bed fusion using in situ high-speed synchrotron x-ray imaging Ti-6Al-4V激光粉末床熔合的原位高速同步x射线成像工艺图

IF 11.1 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-09-05 DOI: 10.1016/j.addma.2025.105007

Elena Ruckh , Rubén Lambert-Garcia , Samy Hocine , Anna C.M. Getley , Caterina Iantaffi , Alisha Bhatt , Maureen Fitzpatrick , Sebastian Marussi , Andy Farndell , Tim Schubert , Gaby Ketzer-Raichle , Marta Majkut , Alexander Rack , Nick Jones , Chu Lun Alex Leung , Peter D. Lee

Laser-based powder bed fusion (PBF-LB) of Ti-6Al-4V enables the manufacturing of strong, lightweight, and complex components for high-value engineering applications. Producing reliable safety-critical PBF-LB parts requires an in-depth understanding and control of the laser-material interaction, melt pool and defect dynamics. This study employs in situ high-speed synchrotron X-ray imaging to produce a laser power and scan speed (P-v) process map for Ti-6Al-4V single-layer tracks across industrially relevant conditions (P = 100–500 W and v = 250–2000 mm s⁻¹) with a 60 µm powder layer thickness and 85 µm laser spot size. The process map identifies three distinct melting regimes: keyhole, tailed vapour depression, and pure conduction mode, separated into stable and unstable conditions, with associated features, such as porosity and surface perturbations (high- and low-amplitude) and end-of-track defects. Key geometric thresholds include vapour cavity depth-to-length ratios of ∼0.33 and ∼2.9, which mark boundaries for surface perturbations and pore formation. To minimise keyhole porosity, linear energy densities > 0.345 J mm⁻¹ should be avoided, while > 0.075 J mm⁻¹ is required to form a vapour cavity. Among the process parameter combinations, the defect-lean condition with the highest scan speed of 1600 mm s^–1 at 350 W is recommended. This comprehensive process mapping facilitates the identification of a stable processing window optimised for high productivity and defect-lean components.

Ti-6Al-4V的激光粉末床熔合（PBF-LB）可以为高价值的工程应用制造坚固、轻量化和复杂的组件。生产可靠的安全关键PBF-LB部件需要深入了解和控制激光材料相互作用、熔池和缺陷动力学。本研究采用原位高速同步x射线成像技术，在工业相关条件下（P = 100-500 W和v = 250-2000 mm s - 1），为Ti-6Al-4V单层磁道制作激光功率和扫描速度（P-v）工艺图，粉末层厚度为60 µm，激光光斑尺寸为85 µm。工艺图确定了三种不同的熔化模式：锁孔，尾部蒸汽下降和纯传导模式，分为稳定和不稳定的条件，具有相关的特征，如孔隙率和表面扰动（高振幅和低振幅）以及轨迹末端缺陷。关键的几何阈值包括蒸汽腔深度-长度比为~ 0.33和~ 2.9，这标志着表面扰动和孔隙形成的边界。为了使锁孔孔隙率最小化，应避免线能量密度>； 0.345 J mm - 1，而形成气腔所需的线能量密度>； 0.075 J mm - 1。在工艺参数组合中，建议采用最高扫描速度为1600 mm s-1、350 W的缺陷倾斜条件。这种全面的过程映射有助于确定稳定的处理窗口，以优化高生产率和低缺陷组件。

{"title":"Process mapping of Ti-6Al-4V laser powder bed fusion using in situ high-speed synchrotron x-ray imaging","authors":"Elena Ruckh , Rubén Lambert-Garcia , Samy Hocine , Anna C.M. Getley , Caterina Iantaffi , Alisha Bhatt , Maureen Fitzpatrick , Sebastian Marussi , Andy Farndell , Tim Schubert , Gaby Ketzer-Raichle , Marta Majkut , Alexander Rack , Nick Jones , Chu Lun Alex Leung , Peter D. Lee","doi":"10.1016/j.addma.2025.105007","DOIUrl":"10.1016/j.addma.2025.105007","url":null,"abstract":"<div><div>Laser-based powder bed fusion (PBF-LB) of Ti-6Al-4V enables the manufacturing of strong, lightweight, and complex components for high-value engineering applications. Producing reliable safety-critical PBF-LB parts requires an in-depth understanding and control of the laser-material interaction, melt pool and defect dynamics. This study employs <em>in situ</em> high-speed synchrotron X-ray imaging to produce a laser power and scan speed (<em>P-v</em>) process map for Ti-6Al-4V single-layer tracks across industrially relevant conditions (<em>P</em> = 100–500 W and <em>v</em> = 250–2000 mm s<sup>−1</sup>) with a 60 µm powder layer thickness and 85 µm laser spot size. The process map identifies three distinct melting regimes: keyhole, tailed vapour depression, and pure conduction mode, separated into stable and unstable conditions, with associated features, such as porosity and surface perturbations (high- and low-amplitude) and end-of-track defects. Key geometric thresholds include vapour cavity depth-to-length ratios of ∼0.33 and ∼2.9, which mark boundaries for surface perturbations and pore formation. To minimise keyhole porosity, linear energy densities > 0.345 J mm<sup>−1</sup> should be avoided, while > 0.075 J mm<sup>−1</sup> is required to form a vapour cavity. Among the process parameter combinations, the defect-lean condition with the highest scan speed of 1600 mm s<sup>–1</sup> at 350 W is recommended. This comprehensive process mapping facilitates the identification of a stable processing window optimised for high productivity and defect-lean components.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"113 ","pages":"Article 105007"},"PeriodicalIF":11.1,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145428820","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}

引用次数: 0

An orientation-based homogenization approach for predicting process-induced deformations in extrusion-based additive manufacturing 基于取向的均匀化方法预测挤压增材制造过程中引起的变形

IF 11.1 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-09-05 DOI: 10.1016/j.addma.2025.105023

Felix Frölich , Mario Emanuele Di Nardo , Constantin Krauß , Anselm Heuer , Wilfried V. Liebig , Florian Wittemann , Pierpaolo Carlone , Luise Kärger

This work presents a homogenization approach for considering process-specific mesostructures typical for material extrusion in finite element simulations to predict process-induced deformation. The approach is based on adapted orientation tensors and orientation averaging, accounting for the characteristic mesostructure and directionality of the material extrusion process. The method addresses the challenge of modeling mesostructural effects across entire components with computationally feasible element sizes. It is implemented in Python and Abaqus, and validated experimentally with PLA, showing good agreement between measured and predicted process-induced deformation. Comparative simulations with an isotropic stiffness formulation demonstrate the significant impact of considering mesostructural anisotropy, highlighting improvements over conventional approaches. Numerical studies further show the evolution of effective material orientation during printing, underscoring the advantages of the anisotropic approach. This method enables efficient, physically consistent integration of material extrusion mesostructures into process-induced deformation prediction, supporting enhanced process design and reliability in material extrusion manufactured components.

这项工作提出了一种均质化方法，用于考虑有限元模拟中材料挤压典型的工艺特定细观结构，以预测工艺引起的变形。该方法基于自适应取向张量和取向平均，考虑了材料挤压过程的细观结构特征和方向性。该方法解决了在计算上可行的单元尺寸的整个组件之间模拟细观结构效应的挑战。该方法在Python和Abaqus中实现，并在PLA中进行了实验验证，结果表明，测量的过程引起的变形与预测的过程引起的变形吻合良好。与各向同性刚度公式的比较模拟表明，考虑细观结构各向异性的显著影响，突出了传统方法的改进。数值研究进一步显示了打印过程中有效材料取向的演变，强调了各向异性方法的优势。该方法能够将材料挤压细观结构有效地、物理上一致地集成到过程引起的变形预测中，支持增强的过程设计和材料挤压制造部件的可靠性。

{"title":"An orientation-based homogenization approach for predicting process-induced deformations in extrusion-based additive manufacturing","authors":"Felix Frölich , Mario Emanuele Di Nardo , Constantin Krauß , Anselm Heuer , Wilfried V. Liebig , Florian Wittemann , Pierpaolo Carlone , Luise Kärger","doi":"10.1016/j.addma.2025.105023","DOIUrl":"10.1016/j.addma.2025.105023","url":null,"abstract":"<div><div>This work presents a homogenization approach for considering process-specific mesostructures typical for material extrusion in finite element simulations to predict process-induced deformation. The approach is based on adapted orientation tensors and orientation averaging, accounting for the characteristic mesostructure and directionality of the material extrusion process. The method addresses the challenge of modeling mesostructural effects across entire components with computationally feasible element sizes. It is implemented in <em>Python</em> and <em>Abaqus</em>, and validated experimentally with PLA, showing good agreement between measured and predicted process-induced deformation. Comparative simulations with an isotropic stiffness formulation demonstrate the significant impact of considering mesostructural anisotropy, highlighting improvements over conventional approaches. Numerical studies further show the evolution of effective material orientation during printing, underscoring the advantages of the anisotropic approach. This method enables efficient, physically consistent integration of material extrusion mesostructures into process-induced deformation prediction, supporting enhanced process design and reliability in material extrusion manufactured components.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"113 ","pages":"Article 105023"},"PeriodicalIF":11.1,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569432","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}

引用次数: 0

Self-supporting mid-air 3D printing of single-layer polypropylene structures: Flow rate-dependent analytical modeling and surface characterization 单层聚丙烯结构的自支撑半空3D打印：流速相关的分析建模和表面表征

IF 11.1 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-09-05 DOI: 10.1016/j.addma.2025.105010

Alexander A. Altmann , Sven Suppelt , Philipp Wüst , Jan Helge Dörsam , Bastian Latsch , Dennis Flachs , Andreas Blaeser , Xiaoqing Zhang , Christiane Thielemann , Heinz von Seggern , Mario Kupnik

High-precision deposition in material extrusion-based additive manufacturing (MEX-AM), especially in mid-air extrusion, is essential for creating microfluidic channels, integrated sensors, and tissue scaffolds with fine vascular features. However, despite advances in support-free slicing and multi-axis printing, no standardized method exists for fabricating enclosed air cavities with high shape fidelity, particularly in single-layer structures. Reliable deposition at sub-millimeter scales remains challenging, especially when printing low-stiffness polymers such as polypropylene (PP), due to delayed solidification and viscoelastic effects. This study introduces a flow-rate-dependent analytical model to predict extrusion behavior, interfacial bonding, and surface morphology in self-supporting single-layer PP structures. To validate the model, surface roughness, material distribution, and intralayer bonding were quantified using spectral analysis, cross-sectional thickness measurements, and Abbott–Firestone curve evaluation. Results show that reducing the flow rate (relative to 100% nominal flow through a 0.4 mm nozzle) to 40% improves surface roughness (Ra) to below 20

μ

m on average across all surfaces, with the lowest Ra of 4.52 ± 0.49

μ

m observed at a 20% flow rate on the top surfaces enclosing the cavity. The intralayer bonding between adjacent extruded lines increases up to 70%, improving deposition uniformity. Nozzle-induced smoothing effects enhance surface quality at flow rates of 60% or lower, while higher flow rates result in increased surface waviness and geometric irregularities. These findings enable the fabrication of enclosed microfluidic channels and functional cavities with well-defined surfaces and reduced mechanical stiffness, suitable for applications involving sensing, controlled deformation, or flexible system integration.

基于材料挤压的增材制造（MEX-AM）中的高精度沉积，特别是在空中挤压中，对于创建具有精细血管特征的微流体通道，集成传感器和组织支架至关重要。然而，尽管在无支撑切片和多轴打印方面取得了进展，但目前还没有标准化的方法来制造具有高形状保真度的封闭气腔，特别是在单层结构中。由于延迟固化和粘弹性效应，在亚毫米尺度上可靠的沉积仍然具有挑战性，特别是在打印聚丙烯（PP）等低刚度聚合物时。本研究引入了流速相关的分析模型来预测自支撑单层PP结构的挤出行为、界面结合和表面形态。为了验证模型，使用光谱分析、横截面厚度测量和abbot - firestone曲线评估对表面粗糙度、材料分布和层内粘合进行了量化。结果表明，将流量（相对于0.4 mm喷嘴的100%标称流量）降低到40%，所有表面的平均粗糙度（Ra）降至20 μm以下，当流量为20%时，围腔顶部表面的Ra最低，为4.52±0.49 μm。相邻挤压线之间的层内结合提高了70%，提高了沉积均匀性。当流量为60%或更低时，喷嘴诱导的平滑效应会提高表面质量，而更高的流量会增加表面波纹度和几何不规则性。这些发现使得封闭微流体通道和具有明确表面和降低机械刚度的功能腔的制造成为可能，适用于涉及传感、控制变形或柔性系统集成的应用。

{"title":"Self-supporting mid-air 3D printing of single-layer polypropylene structures: Flow rate-dependent analytical modeling and surface characterization","authors":"Alexander A. Altmann , Sven Suppelt , Philipp Wüst , Jan Helge Dörsam , Bastian Latsch , Dennis Flachs , Andreas Blaeser , Xiaoqing Zhang , Christiane Thielemann , Heinz von Seggern , Mario Kupnik","doi":"10.1016/j.addma.2025.105010","DOIUrl":"10.1016/j.addma.2025.105010","url":null,"abstract":"<div><div>High-precision deposition in material extrusion-based additive manufacturing (MEX-AM), especially in mid-air extrusion, is essential for creating microfluidic channels, integrated sensors, and tissue scaffolds with fine vascular features. However, despite advances in support-free slicing and multi-axis printing, no standardized method exists for fabricating enclosed air cavities with high shape fidelity, particularly in single-layer structures. Reliable deposition at sub-millimeter scales remains challenging, especially when printing low-stiffness polymers such as polypropylene (PP), due to delayed solidification and viscoelastic effects. This study introduces a flow-rate-dependent analytical model to predict extrusion behavior, interfacial bonding, and surface morphology in self-supporting single-layer PP structures. To validate the model, surface roughness, material distribution, and intralayer bonding were quantified using spectral analysis, cross-sectional thickness measurements, and Abbott–Firestone curve evaluation. Results show that reducing the flow rate (relative to 100% nominal flow through a 0.4 mm nozzle) to 40% improves surface roughness (Ra) to below 20   <span><math><mi>μ</mi></math></span>m observed at a 20% flow rate on the top surfaces enclosing the cavity. The intralayer bonding between adjacent extruded lines increases up to 70%, improving deposition uniformity. Nozzle-induced smoothing effects enhance surface quality at flow rates of 60% or lower, while higher flow rates result in increased surface waviness and geometric irregularities. These findings enable the fabrication of enclosed microfluidic channels and functional cavities with well-defined surfaces and reduced mechanical stiffness, suitable for applications involving sensing, controlled deformation, or flexible system integration.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"113 ","pages":"Article 105010"},"PeriodicalIF":11.1,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145464711","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}

引用次数: 0

Low-dimensional shrinkage and high-performance SiC ceramics fabricated by MEX printing combined with PIP and pressureless solid-state sintering 用MEX打印结合PIP和无压固态烧结制备低维收缩高性能SiC陶瓷

IF 11.1 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-09-05 DOI: 10.1016/j.addma.2025.105024

Chenxi Gao , Jian Chen , Shengjun Liao , Changcong Huang , Lan Peng , Jiashen Chen , Zhongming Chen , Zhengren Huang

In this study, the precursor infiltration and pyrolysis (PIP) process was implemented during the post-debinding phase of silicon carbide (SiC) ceramics to mitigate the issue of excessive dimensional shrinkage associated with material extrusion (MEX) 3D printing followed by pressureless solid-state sintering. Variations in dimensional stability and material properties were identified by comparing different processing routes, including direct PIP, pre-sintering followed by PIP, and pre-sintering combined with PIP and re-sintering. The results demonstrated that introducing PIP between debinding and sintering significantly reduced linear shrinkage during pressureless sintering from 21.71 % (direct sintering) to a minimum of 6.38 %. Concurrently, the PIP treatment markedly enhanced the densification of the material, achieving a maximum density of 3.17 g·cm^-³ and a flexural strength of 359 MPa after re-sintering. Furthermore, the SiC ceramics fabricated via this route exhibit exceptional thermal conductivity and high-temperature mechanical properties, reaching up to 165.76 W·m⁻¹·K⁻¹ and a flexural strength of 357 MPa at 1500 °C, respectively.

在这项研究中，在碳化硅（SiC）陶瓷的脱粘后阶段实施了前驱体渗透和热解（PIP）过程，以减轻材料挤压（MEX） 3D打印（随后进行无压固态烧结）带来的尺寸过度收缩问题。通过比较不同的工艺路线，包括直接PIP，预烧结后PIP，预烧结结合PIP和再烧结，确定了尺寸稳定性和材料性能的变化。结果表明，在脱脂和烧结之间引入PIP可显著降低无压烧结时的线收缩率，从21.71 %（直接烧结）降至最低6.38 %。同时，PIP处理显著增强了材料的致密化，再烧结后的最大密度为3.17 g·cm-³，抗弯强度为359 MPa。此外，通过这种方法制备的SiC陶瓷具有优异的导热性和高温力学性能，在1500°C时的弯曲强度分别达到165.76 W·m⁻¹·K⁻¹和357 MPa。

{"title":"Low-dimensional shrinkage and high-performance SiC ceramics fabricated by MEX printing combined with PIP and pressureless solid-state sintering","authors":"Chenxi Gao , Jian Chen , Shengjun Liao , Changcong Huang , Lan Peng , Jiashen Chen , Zhongming Chen , Zhengren Huang","doi":"10.1016/j.addma.2025.105024","DOIUrl":"10.1016/j.addma.2025.105024","url":null,"abstract":"<div><div>In this study, the precursor infiltration and pyrolysis (PIP) process was implemented during the post-debinding phase of silicon carbide (SiC) ceramics to mitigate the issue of excessive dimensional shrinkage associated with material extrusion (MEX) 3D printing followed by pressureless solid-state sintering. Variations in dimensional stability and material properties were identified by comparing different processing routes, including direct PIP, pre-sintering followed by PIP, and pre-sintering combined with PIP and re-sintering. The results demonstrated that introducing PIP between debinding and sintering significantly reduced linear shrinkage during pressureless sintering from 21.71 % (direct sintering) to a minimum of 6.38 %. Concurrently, the PIP treatment markedly enhanced the densification of the material, achieving a maximum density of 3.17 g·cm<sup>-</sup>³ and a flexural strength of 359 MPa after re-sintering. Furthermore, the SiC ceramics fabricated via this route exhibit exceptional thermal conductivity and high-temperature mechanical properties, reaching up to 165.76 W·m⁻¹·K⁻¹ and a flexural strength of 357 MPa at 1500 °C, respectively.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"113 ","pages":"Article 105024"},"PeriodicalIF":11.1,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145518219","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}

引用次数: 0

Understanding the interfacial bonding mechanism and its impact on mechanical performance in SS316L/Cu functionally graded materials produced by laser powder bed fusion 了解激光粉末床熔合制备SS316L/Cu功能梯度材料的界面键合机制及其对力学性能的影响

IF 11.1 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-09-05 DOI: 10.1016/j.addma.2025.105019

Xihang Yu , Weihao Yuan , Wenpeng Wan , Pengfei Yu , Wenya Li , Zhaoguo Qiu , Chao Zhang , Chunjie Huang , Shuo Yin

The microstructural evolution, interfacial bonding mechanism and mechanical properties of the stainless steel 316 L/Cu (SS316L/Cu) functionally graded material (FGM) fabricated by depositing SS316L on Cu via powder bed fusion - laser beam (PBF-LB) were investigated. A combination of experimental characterization and computational modelling were employed for a comprehensive study. Existing studies have mainly focused on depositing Cu on steel . However, in this study, the inverse deposition sequence, i.e. steel on Cu is investigated to fabricate the FGM with fewer defects and desirable elongation and strength. Microscopic analyses revealed that vortex-like intermixing zone can be generated during PBF-LB process, which effectively locked Cu and SS316L phases at the interfacial fusion region (IFR). This intermixing zone enabled a coordinated deformation between Cu and SS316L, and delayed the occurrence of necking and improved the ductility of Cu during the tensile loading of the FGM. However, during the tensile test, the crack propagation from Cu into SS316L reduced the latter’s effective elongation, resulting in an overall FGM elongation ranging from 19 % to 21 %, and a fracture fusion region (FFR) spanning 150–200μm, which consisted of approximately 70–80 % SS316L and 30–20 % Cu. Further analysis identified a dual embedding mechanism at the SS316L/Cu IFR which is featured with nano-structural intermixing, voids embedded within Cu and mutual embedding of Fe and Cu nanoparticles. Apart from the nano-scale mutual embedding, the IFR was also characterized with refined grain structures, high dislocation densities, intermetallic, solid solution, and dominant high-angle grain boundaries and corresponding strengthening and failure mechanisms are discussed. These factors worked together and eventually contributed to the good mechanical performance of the FGM. The findings in this study provided critical insight into the design of dissimilar metal FGMs and validate the steel/Cu FGM for structural applications requiring both strength and ductility.

研究了采用粉末床熔合激光（PBF-LB）在Cu表面沉积SS316L制备的316不锈钢 L/Cu （SS316L/Cu）功能梯度材料（FGM）的显微组织演变、界面结合机制和力学性能。采用实验表征和计算建模相结合的方法进行了全面的研究。现有的研究主要集中在铜在钢上的沉积。然而，在本研究中，研究了逆沉积顺序，即钢在Cu上的沉积，以制备具有较少缺陷和理想伸长率和强度的FGM。微观分析表明，在PBF-LB过程中产生了涡状混合区，有效地将Cu和SS316L相锁定在界面融合区（IFR）。该混合区使Cu与SS316L发生协调变形，延缓了缩颈的发生，提高了FGM拉伸加载过程中Cu的延性。然而，在拉伸试验中，从Cu到SS316L的裂纹扩展降低了后者的有效伸长率，导致整体FGM伸长率在19 % ~ 21 %之间，断口融合区（FFR）跨越150 ~ 200μm，由大约70 ~ 80 % SS316L和30 ~ 20 % Cu组成。进一步分析发现，在SS316L/Cu IFR中存在双重包埋机制，即纳米结构混合、Cu内部嵌入孔洞以及Fe和Cu纳米颗粒相互包埋。除了在纳米尺度上相互包埋外，IFR还具有晶粒结构精细、位错密度高、金属间、固溶、高角晶界为主的特点，并讨论了相应的强化和破坏机制。这些因素共同作用，最终促成了FGM良好的机械性能。本研究的发现为异种金属FGM的设计提供了重要的见解，并验证了钢/Cu FGM在要求强度和延展性的结构应用中的应用。

{"title":"Understanding the interfacial bonding mechanism and its impact on mechanical performance in SS316L/Cu functionally graded materials produced by laser powder bed fusion","authors":"Xihang Yu , Weihao Yuan , Wenpeng Wan , Pengfei Yu , Wenya Li , Zhaoguo Qiu , Chao Zhang , Chunjie Huang , Shuo Yin","doi":"10.1016/j.addma.2025.105019","DOIUrl":"10.1016/j.addma.2025.105019","url":null,"abstract":"<div><div>The microstructural evolution, interfacial bonding mechanism and mechanical properties of the stainless steel 316 L/Cu (SS316L/Cu) functionally graded material (FGM) fabricated by depositing SS316L on Cu via powder bed fusion - laser beam (PBF-LB) were investigated. A combination of experimental characterization and computational modelling were employed for a comprehensive study. Existing studies have mainly focused on depositing Cu on steel . However, in this study, the inverse deposition sequence, i.e. steel on Cu is investigated to fabricate the FGM with fewer defects and desirable elongation and strength. Microscopic analyses revealed that vortex-like intermixing zone can be generated during PBF-LB process, which effectively locked Cu and SS316L phases at the interfacial fusion region (IFR). This intermixing zone enabled a coordinated deformation between Cu and SS316L, and delayed the occurrence of necking and improved the ductility of Cu during the tensile loading of the FGM. However, during the tensile test, the crack propagation from Cu into SS316L reduced the latter’s effective elongation, resulting in an overall FGM elongation ranging from 19 % to 21 %, and a fracture fusion region (FFR) spanning 150–200μm, which consisted of approximately 70–80 % SS316L and 30–20 % Cu. Further analysis identified a dual embedding mechanism at the SS316L/Cu IFR which is featured with nano-structural intermixing, voids embedded within Cu and mutual embedding of Fe and Cu nanoparticles. Apart from the nano-scale mutual embedding, the IFR was also characterized with refined grain structures, high dislocation densities, intermetallic, solid solution, and dominant high-angle grain boundaries and corresponding strengthening and failure mechanisms are discussed. These factors worked together and eventually contributed to the good mechanical performance of the FGM. The findings in this study provided critical insight into the design of dissimilar metal FGMs and validate the steel/Cu FGM for structural applications requiring both strength and ductility.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"113 ","pages":"Article 105019"},"PeriodicalIF":11.1,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145518220","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}

引用次数: 0

Phase transformations in hypoeutectoid carbon steel during laser powder bed fusion 亚共析碳钢在激光粉末床熔合过程中的相变

IF 11.1 1区工程技术 Q1 ENGINEERING, MANUFACTURING

Additive manufacturing

Pub Date : 2025-09-05 DOI: 10.1016/j.addma.2025.105020

William Hearn , Sneha Goel , Camille Pauzon , Abdul Shaafi Shaikh , Nicola Casati , Eduard Hryha , Steven Van Petegem

This study employed high-speed in situ X-ray diffraction, combined with modeling and simulation, to investigate the phase transformations in Fe-0.45 C steel during laser powder bed fusion (L-PBF). The observed rapid cooling rates (∼8.4*10⁴ K/s to ∼7.7*10⁵ K/s) induced two phase transformation shifts. First, the primary solidification mode shifted from δ-ferrite to austenite, aligning with predictions from the Kurz-Giovanola-Trivedi solidification model. Second, austenite transformed into martensite as the cooling rates exceeded the threshold for fully martensitic microstructure (∼500 K/s). Ex situ analyses further confirmed a martensitic microstructure, as the specimens were characterized by a high hardness (∼750–780 HV), fine lath morphology, unetched appearance, and a body centered tetragonal lattice structure. Martensite tempering during the intrinsic heat treatment (IHT) occurred primarily during the initial three cycles, with the most pronounced effect occurring after the first cycle. This was attributed to the efficient heat dissipation of the thin-wall specimens, which minimized heat accumulation and resulted in tempering being driven by reheating within the heat-affected zone. Further phase analysis and modeling identified cementite as the dominant carbide within tempered martensite, even after the first IHT cycle. This was linked to the high dislocation density, small parent grain size, and fine sub-grain structure of martensite, which facilitated transition carbide dissolution while accelerating cementite nucleation and growth. These findings provide an important understanding of microstructure formation during L-PBF of hypo-eutectoid carbon steels that can serve as a baseline for the development of alloy compositions that are tailored for the process.

本研究采用高速原位x射线衍射，结合建模和仿真，研究了Fe-0.45 C钢在激光粉末床熔合过程中的相变。观察到的快速冷却速率（~ 8.4*10⁴K/s至~ 7.7*10⁴K/s）诱导了两次相变。首先，初始凝固模式从δ-铁素体转变为奥氏体，这与Kurz-Giovanola-Trivedi凝固模型的预测一致。其次，当冷却速率超过完全马氏体组织的阈值（~ 500 K/s）时，奥氏体转变为马氏体。非原位分析进一步证实了马氏体微观结构，因为样品具有高硬度（~ 750-780 HV），精细的板条形貌，无蚀刻外观和体中心的四边形晶格结构。本征热处理（IHT）过程中的马氏体回火主要发生在前三个循环中，在第一个循环之后效果最为明显。这是由于薄壁试样的有效散热，最大限度地减少了热量积累，导致回火是由热影响区内的再加热驱动的。进一步的相分析和建模表明，即使在第一次高温循环之后，渗碳体仍是回火马氏体中的主要碳化物。这与马氏体的位错密度高、母晶尺寸小、亚晶结构细有关，有利于过渡碳化物的溶解，加速渗碳体的形核和生长。这些发现提供了对亚共析碳钢L-PBF过程中微观结构形成的重要理解，可以作为开发适合该工艺的合金成分的基线。

{"title":"Phase transformations in hypoeutectoid carbon steel during laser powder bed fusion","authors":"William Hearn , Sneha Goel , Camille Pauzon , Abdul Shaafi Shaikh , Nicola Casati , Eduard Hryha , Steven Van Petegem","doi":"10.1016/j.addma.2025.105020","DOIUrl":"10.1016/j.addma.2025.105020","url":null,"abstract":"<div><div>This study employed high-speed in situ X-ray diffraction, combined with modeling and simulation, to investigate the phase transformations in Fe-0.45 C steel during laser powder bed fusion (L-PBF). The observed rapid cooling rates (∼8.4*10⁴ K/s to ∼7.7*10⁵ K/s) induced two phase transformation shifts. First, the primary solidification mode shifted from δ-ferrite to austenite, aligning with predictions from the Kurz-Giovanola-Trivedi solidification model. Second, austenite transformed into martensite as the cooling rates exceeded the threshold for fully martensitic microstructure (∼500 K/s). Ex situ analyses further confirmed a martensitic microstructure, as the specimens were characterized by a high hardness (∼750–780 HV), fine lath morphology, unetched appearance, and a body centered tetragonal lattice structure. Martensite tempering during the intrinsic heat treatment (IHT) occurred primarily during the initial three cycles, with the most pronounced effect occurring after the first cycle. This was attributed to the efficient heat dissipation of the thin-wall specimens, which minimized heat accumulation and resulted in tempering being driven by reheating within the heat-affected zone. Further phase analysis and modeling identified cementite as the dominant carbide within tempered martensite, even after the first IHT cycle. This was linked to the high dislocation density, small parent grain size, and fine sub-grain structure of martensite, which facilitated transition carbide dissolution while accelerating cementite nucleation and growth. These findings provide an important understanding of microstructure formation during L-PBF of hypo-eutectoid carbon steels that can serve as a baseline for the development of alloy compositions that are tailored for the process.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"113 ","pages":"Article 105020"},"PeriodicalIF":11.1,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145518280","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}

引用次数: 0