Pub Date : 2024-07-01DOI: 10.1016/j.addlet.2024.100228
Nadia Azizi , Hamed Asgari , Ehsan Toyserkani
The oxidation behavior of copper-silver (Cu–Ag) alloy with the structure of triply periodic minimal surfaces (TPMS) processed by laser powder bed fusion (LPBF) was investigated at 300 °C and 600 °C. The lightweight TPMSs increase surface area, boosting measurement sensitivity in oxidation studies. The presence of silver enhances oxidation resistance of Cu–Ag alloy compared to that of pure copper by slowing down the oxidation process and thinning the oxide layer. This suggests that silver in the alloy potentially suppresses the outward diffusion of copper from the substrate to the oxide layer. This effect is evident in the oxidation rate curves, where the introduction of silver changes the oxidation kinetics from a linear rate in Cu to a parabolic rate in Cu–2 wt.% Ag at 300 °C. Moreover, at 600 °C, silver induces a slower parabolic rate in Cu–2 wt.% Ag compared to Cu.
通过激光粉末床熔融(LPBF)技术,研究了具有三重周期性极小表面(TPMS)结构的铜银(Cu-Ag)合金在 300 ℃ 和 600 ℃ 下的氧化行为。轻质 TPMS 增加了表面积,提高了氧化研究中的测量灵敏度。与纯铜相比,银的存在通过减缓氧化过程和减薄氧化层增强了铜银合金的抗氧化性。这表明合金中的银有可能抑制铜从基底向氧化层的向外扩散。这种效应在氧化速率曲线中很明显,在 300 °C 时,银的引入使氧化动力学从铜的线性速率变为 Cu-2 wt.% Ag 的抛物线速率。此外,在 600 °C 时,与铜相比,银在 Cu-2 wt.% Ag 中产生的抛物线速率更慢。
{"title":"Oxidation behavior of Cu–Ag alloy in-situ manufactured via laser powder bed fusion","authors":"Nadia Azizi , Hamed Asgari , Ehsan Toyserkani","doi":"10.1016/j.addlet.2024.100228","DOIUrl":"10.1016/j.addlet.2024.100228","url":null,"abstract":"<div><p>The oxidation behavior of copper-silver (Cu–Ag) alloy with the structure of triply periodic minimal surfaces (TPMS) processed by laser powder bed fusion (LPBF) was investigated at 300 °C and 600 °C. The lightweight TPMSs increase surface area, boosting measurement sensitivity in oxidation studies. The presence of silver enhances oxidation resistance of Cu–Ag alloy compared to that of pure copper by slowing down the oxidation process and thinning the oxide layer. This suggests that silver in the alloy potentially suppresses the outward diffusion of copper from the substrate to the oxide layer. This effect is evident in the oxidation rate curves, where the introduction of silver changes the oxidation kinetics from a linear rate in Cu to a parabolic rate in Cu–2 wt.% Ag at 300 °C. Moreover, at 600 °C, silver induces a slower parabolic rate in Cu–2 wt.% Ag compared to Cu.</p></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"10 ","pages":"Article 100228"},"PeriodicalIF":4.2,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772369024000367/pdfft?md5=713a77b8b84719c9ade147ebbd06e5b6&pid=1-s2.0-S2772369024000367-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141962059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-07DOI: 10.1016/j.addlet.2024.100220
Matthias Markl, Mohammad Reza Azadi Tinat, Timo Berger, Jakob Renner, Carolin Körner
Electron beam powder bed fusion offers the unique opportunity to observe the process by measuring scattered electrons on a metal detector. This technique is the state of the art in generating electron optical images of the build area after melting using single- or multi-detector setups. The images enable the detection of surface defects like porosity or material transport by reconstructing the surface topography. Internal defects such as layer-bonding defects cannot be identified. Many of these defects, particularly layer-bonding defects, often originate from an irregular distribution of the powder bed.
This work introduces an additional process step by recording an electron optical image after the distribution of the powder bed. Combining this with an electron optical image after melting the previous layer enables extraction of powder bed features such as the current powder bed height. The underlying method bases on the correlation of experimental measurements and numerical simulations of the intensity of the electron optical signal for different powder bed heights. With this approach, it is possible to identify irregular powder distributions, such as uncovered areas of previously molten material or locally varying powder bed heights. This information is crucial for online monitoring and real time process control. Exemplary, this opens the opportunity of healing the powder bed by an additional raking step.
{"title":"Extracting powder bed features via electron optical images during electron beam powder bed fusion","authors":"Matthias Markl, Mohammad Reza Azadi Tinat, Timo Berger, Jakob Renner, Carolin Körner","doi":"10.1016/j.addlet.2024.100220","DOIUrl":"https://doi.org/10.1016/j.addlet.2024.100220","url":null,"abstract":"<div><p>Electron beam powder bed fusion offers the unique opportunity to observe the process by measuring scattered electrons on a metal detector. This technique is the state of the art in generating electron optical images of the build area after melting using single- or multi-detector setups. The images enable the detection of surface defects like porosity or material transport by reconstructing the surface topography. Internal defects such as layer-bonding defects cannot be identified. Many of these defects, particularly layer-bonding defects, often originate from an irregular distribution of the powder bed.</p><p>This work introduces an additional process step by recording an electron optical image after the distribution of the powder bed. Combining this with an electron optical image after melting the previous layer enables extraction of powder bed features such as the current powder bed height. The underlying method bases on the correlation of experimental measurements and numerical simulations of the intensity of the electron optical signal for different powder bed heights. With this approach, it is possible to identify irregular powder distributions, such as uncovered areas of previously molten material or locally varying powder bed heights. This information is crucial for online monitoring and real time process control. Exemplary, this opens the opportunity of healing the powder bed by an additional raking step.</p></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"10 ","pages":"Article 100220"},"PeriodicalIF":0.0,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S277236902400029X/pdfft?md5=bcfec8a21ec24fa6bea53ac48b89eac6&pid=1-s2.0-S277236902400029X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140918694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-03DOI: 10.1016/j.addlet.2024.100217
Simon Teves , Tobias Biermann , Arved Ziebehl , Jan Gerrit Eckert , Ole Hill , Panpan Xia , Merve Wollweber , Tammo Ripken , Nadja C. Bigall , Roland Lachmayer
Multi-Material Additive Manufacturing (MMAM) enables the grading of material properties and the integration of functions within printed parts. While most MMAM methods are limited to process single-component or pre-mixed multi-component materials, the in-process mixing and extrusion of multi-component materials enables innovative material properties and use cases. When processing liquid multi-component materials, the individual component streams need to be homogenized in-process, but the required volume in conventional passive mixing hinders rapid transitions in material composition. In this paper, a two component printhead is presented which combines an active mixing approach with a continuous composition adjustment for a third additive. The approach to control the mixing composition is to influence the hydrodynamic equilibrium of individual material streams before merging them near the point of extrusion. The printhead’s functionality is verified in terms of mixing homogeneity and transition speed between material compositions.
{"title":"Active-mixing printhead for on-the-fly composition adjustment of multi component materials in Direct Ink Writing","authors":"Simon Teves , Tobias Biermann , Arved Ziebehl , Jan Gerrit Eckert , Ole Hill , Panpan Xia , Merve Wollweber , Tammo Ripken , Nadja C. Bigall , Roland Lachmayer","doi":"10.1016/j.addlet.2024.100217","DOIUrl":"https://doi.org/10.1016/j.addlet.2024.100217","url":null,"abstract":"<div><p>Multi-Material Additive Manufacturing (MMAM) enables the grading of material properties and the integration of functions within printed parts. While most MMAM methods are limited to process single-component or pre-mixed multi-component materials, the in-process mixing and extrusion of multi-component materials enables innovative material properties and use cases. When processing liquid multi-component materials, the individual component streams need to be homogenized in-process, but the required volume in conventional passive mixing hinders rapid transitions in material composition. In this paper, a two component printhead is presented which combines an active mixing approach with a continuous composition adjustment for a third additive. The approach to control the mixing composition is to influence the hydrodynamic equilibrium of individual material streams before merging them near the point of extrusion. The printhead’s functionality is verified in terms of mixing homogeneity and transition speed between material compositions.</p></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"10 ","pages":"Article 100217"},"PeriodicalIF":0.0,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772369024000264/pdfft?md5=8321dcf3b16587f2187170572a05c295&pid=1-s2.0-S2772369024000264-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140880443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-01DOI: 10.1016/j.addlet.2024.100219
Omer Cakmak , Seong Gyu Chung , Seung-Hoon Lee , JiHoe Koo , Hwasung Yeom , Jung-Wook Cho
This study investigates the impact of atmospheres (Ar and N2) on Fe-12Cr-6Al alloy fabricated using laser powder bed fusion (L-PBF) in terms of melt pool shape/size, microstructure, precipitate characteristics, and mechanical properties. The sample built in the N2 atmosphere exhibited lower porosity, wider melt pools, and no Al2O3 agglomeration. Oxygen content decreased from 0.012 to 0.0045 (wt.%), and nitrogen content increased from 0.013 to 0.02 (wt.%). The Ar-printed sample had a yield strength (YS) of 232 ± 15 MPa, ultimate tensile strength (UTS) of 286 ± 10 MPa, and total elongation (TE) of 6.4 ± 1.3 %, while the N2-printed sample showed significant improvements of the mechanical properties: YS of 315 ± 11 MPa, UTS of 401 ± 11 MPa, and TE of 7.8 ± 1.1 %. Therefore, N2 might be considered to replace Ar as a cost-effective shielding gas for FeCrAl alloys, with improved properties.
{"title":"Effect of process atmosphere on microstructure, melt pool, texture, precipitate characteristics, and mechanical properties of laser powder bed fusion Fe-12Cr-6Al","authors":"Omer Cakmak , Seong Gyu Chung , Seung-Hoon Lee , JiHoe Koo , Hwasung Yeom , Jung-Wook Cho","doi":"10.1016/j.addlet.2024.100219","DOIUrl":"https://doi.org/10.1016/j.addlet.2024.100219","url":null,"abstract":"<div><p>This study investigates the impact of atmospheres (Ar and N<sub>2</sub>) on Fe-12Cr-6Al alloy fabricated using laser powder bed fusion (L-PBF) in terms of melt pool shape/size, microstructure, precipitate characteristics, and mechanical properties. The sample built in the N<sub>2</sub> atmosphere exhibited lower porosity, wider melt pools, and no Al<sub>2</sub>O<sub>3</sub> agglomeration. Oxygen content decreased from 0.012 to 0.0045 (wt.%), and nitrogen content increased from 0.013 to 0.02 (wt.%). The Ar-printed sample had a yield strength (YS) of 232 ± 15 MPa, ultimate tensile strength (UTS) of 286 ± 10 MPa, and total elongation (TE) of 6.4 ± 1.3 %, while the N<sub>2</sub>-printed sample showed significant improvements of the mechanical properties: YS of 315 ± 11 MPa, UTS of 401 ± 11 MPa, and TE of 7.8 ± 1.1 %. Therefore, N<sub>2</sub> might be considered to replace Ar as a cost-effective shielding gas for FeCrAl alloys, with improved properties.</p></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"10 ","pages":"Article 100219"},"PeriodicalIF":0.0,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772369024000288/pdfft?md5=ba051126cb68daecf2d4b3acf0654ffb&pid=1-s2.0-S2772369024000288-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140822994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-26DOI: 10.1016/j.addlet.2024.100215
Thomas Grippi , Elisa Torresani , Alberto Cabo Rios , Andrii L. Maximenko , Marco Zago , Ilaria Cristofolini , Alberto Molinari , Rajendra K. Bordia , Eugene A. Olevsky
Using theory and simulations, the challenge of gravity-induced distortions during sintering is addressed and a mitigation strategy is proposed. Based on the continuum theory of sintering, the finite element simulation demonstrates the advantages of a rotating furnace to counteract gravity forces during sintering. Its application for stainless steel hollow parts produced by additive manufacturing (binder jetting) is demonstrated, numerically, for reliable industrial production of complex shapes. Sintering a tube in a very slow rotating motion exhibits an improvement in the final deformation ratio compared to a conventional sintering process.
The same concept has been adapted for higher furnace revolution speeds and the centrifugal force is now surpassing the effects of gravity. An extended study of sintering under microgravity for space-borne applications is also widely depicted with the same model. Indeed, it shows the possibility of reproducing Earth's sintering conditions at places where gravity is insufficient to provide acceptable densification and shape conservation during sintering.
{"title":"Mitigation of gravity-induced distortions of binder-jetting components during rotational sintering","authors":"Thomas Grippi , Elisa Torresani , Alberto Cabo Rios , Andrii L. Maximenko , Marco Zago , Ilaria Cristofolini , Alberto Molinari , Rajendra K. Bordia , Eugene A. Olevsky","doi":"10.1016/j.addlet.2024.100215","DOIUrl":"https://doi.org/10.1016/j.addlet.2024.100215","url":null,"abstract":"<div><p>Using theory and simulations, the challenge of gravity-induced distortions during sintering is addressed and a mitigation strategy is proposed. Based on the continuum theory of sintering, the finite element simulation demonstrates the advantages of a rotating furnace to counteract gravity forces during sintering. Its application for stainless steel hollow parts produced by additive manufacturing (binder jetting) is demonstrated, numerically, for reliable industrial production of complex shapes. Sintering a tube in a very slow rotating motion exhibits an improvement in the final deformation ratio compared to a conventional sintering process.</p><p>The same concept has been adapted for higher furnace revolution speeds and the centrifugal force is now surpassing the effects of gravity. An extended study of sintering under microgravity for space-borne applications is also widely depicted with the same model. Indeed, it shows the possibility of reproducing Earth's sintering conditions at places where gravity is insufficient to provide acceptable densification and shape conservation during sintering.</p></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"10 ","pages":"Article 100215"},"PeriodicalIF":0.0,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772369024000240/pdfft?md5=d925aaba3ed20a08896410422e09d919&pid=1-s2.0-S2772369024000240-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140817081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Melt pool geometry is a deterministic factor affecting the characteristics of metal Additive Manufacturing (AM) components. The wide array of physical and thermal phenomena involved during the formation of the AM melt pool, along with the great variety of alloy compositions and AM methods, coupled with the clear influence of multiple process parameters, make it difficult to predict the melt pool geometry under a given set of conditions. Therefore, using Artificial Intelligence (AI) approaches such as Machine Learning (ML) is necessary for accurate predictions. Using a physics-informed feature selection strategy along with the application of atomic features for the first time, this work aims to offer accurately trained models relying on existing high-fidelity data for most common alloys in AM academia and industry, i.e., 316 L stainless steel, Ti6Al4V, and AlSi10Mg. Multiple ML algorithms were trained, and the results revealed that the average R2 and RMSE obtained by the K-fold cross-validation (K = 5) were significantly enhanced when laser and material properties, inspired by the analytical models for AM melt pool geometry, were used as the model features. Removing the excess features and applying atomic features further enhanced the accuracy of the models. As a result, R2 for the XGBoost, CatBoost, and GPR models were 0.907, 0.889, and 0.882, respectively, while the hold-out cross-validation led to 0.978, 0.976, and 0.945, respectively. Furthermore, the results showed that the XGBoost model outperforms the Rosenthal equation. This approach provides a pathway to more accurately predict the properties of metal AM components.
熔池几何形状是影响金属增材制造 (AM) 部件特性的决定性因素。AM 熔池形成过程中涉及的各种物理和热现象,以及种类繁多的合金成分和 AM 方法,再加上多种工艺参数的明显影响,使得很难预测给定条件下的熔池几何形状。因此,有必要使用人工智能(AI)方法(如机器学习(ML))进行准确预测。这项工作首次使用了物理信息特征选择策略和原子特征应用,旨在根据现有的高保真数据,为 AM 学术界和工业界最常见的合金(即 316 L 不锈钢、Ti6Al4V 和 AlSi10Mg)提供经过精确训练的模型。训练了多种 ML 算法,结果表明,当使用受 AM 熔池几何形状分析模型启发的激光和材料属性作为模型特征时,通过 K 倍交叉验证(K = 5)获得的平均 R2 和 RMSE 显著提高。去除多余特征并应用原子特征进一步提高了模型的准确性。因此,XGBoost、CatBoost 和 GPR 模型的 R2 分别为 0.907、0.889 和 0.882,而保留交叉验证的结果分别为 0.978、0.976 和 0.945。此外,结果显示 XGBoost 模型优于罗森塔尔方程。这种方法为更准确地预测金属 AM 组件的性能提供了一条途径。
{"title":"A novel feature engineering approach for predicting melt pool depth during LPBF by machine learning models","authors":"Mohammad Hossein Mosallanejad , Hassan Gashmard , Mahdi Javanbakht , Behzad Niroumand , Abdollah Saboori","doi":"10.1016/j.addlet.2024.100214","DOIUrl":"https://doi.org/10.1016/j.addlet.2024.100214","url":null,"abstract":"<div><p>Melt pool geometry is a deterministic factor affecting the characteristics of metal Additive Manufacturing (AM) components. The wide array of physical and thermal phenomena involved during the formation of the AM melt pool, along with the great variety of alloy compositions and AM methods, coupled with the clear influence of multiple process parameters, make it difficult to predict the melt pool geometry under a given set of conditions. Therefore, using Artificial Intelligence (AI) approaches such as Machine Learning (ML) is necessary for accurate predictions. Using a physics-informed feature selection strategy along with the application of atomic features for the first time, this work aims to offer accurately trained models relying on existing high-fidelity data for most common alloys in AM academia and industry, i.e., 316 L stainless steel, Ti6Al4V, and AlSi10Mg. Multiple ML algorithms were trained, and the results revealed that the average R<sup>2</sup> and RMSE obtained by the K-fold cross-validation (<em>K</em> = 5) were significantly enhanced when laser and material properties, inspired by the analytical models for AM melt pool geometry, were used as the model features. Removing the excess features and applying atomic features further enhanced the accuracy of the models. As a result, R<sup>2</sup> for the XGBoost, CatBoost, and GPR models were 0.907, 0.889, and 0.882, respectively, while the hold-out cross-validation led to 0.978, 0.976, and 0.945, respectively. Furthermore, the results showed that the XGBoost model outperforms the Rosenthal equation. This approach provides a pathway to more accurately predict the properties of metal AM components.</p></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"10 ","pages":"Article 100214"},"PeriodicalIF":0.0,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772369024000239/pdfft?md5=bd29e5e0479e946efb53b873e042ea15&pid=1-s2.0-S2772369024000239-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140817062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Additive manufacturing of Al alloys has garnered attention in the aerospace and automobile industries. This is the first study on the formation of nanoscale Al precipitates in the Si phase of an AlSi10Mg alloy during electron beam powder bed fusion (EB-PBF). Spherical Si particles were homogeneously dispersed in the Al matrix, highlighting the difference from the laser beam PBF (LB-PBF) microstructures. Nanoscale Al phase was formed with a crystallographic orientation relationship with the surrounding Si phase: (111)Si//(111)Al and [10]Si//[10]Al. The formation of Al nanoprecipitates was attributed to an interplay between non-equilibrium solidification, wherein excess Al was dissolved in the Si particles, and the subsequent decomposition of the supersaturated Si phase during high-temperature exposure owing to the preheating procedure. To the best of our knowledge, such formation of Al nanoparticles has not been reported in AlSi10Mg produced through conventional processing or LB-PBF. Thus, the unique thermal history of EB-PBF provides novel opportunities for microstructural evolution, which may be beneficial for the development of novel Al-based alloys.
{"title":"Nanoscale Al precipitation in the Si phase in AlSi10Mg alloy during electron beam powder bed fusion","authors":"Kenta Ishigami , Kenta Yamanaka , Kenta Aoyagi , Huakang Bian , Yoshiki Hashizume , Akiei Tanaka , Akihiko Chiba","doi":"10.1016/j.addlet.2024.100213","DOIUrl":"https://doi.org/10.1016/j.addlet.2024.100213","url":null,"abstract":"<div><p>Additive manufacturing of Al alloys has garnered attention in the aerospace and automobile industries. This is the first study on the formation of nanoscale Al precipitates in the Si phase of an AlSi10Mg alloy during electron beam powder bed fusion (EB-PBF). Spherical Si particles were homogeneously dispersed in the Al matrix, highlighting the difference from the laser beam PBF (LB-PBF) microstructures. Nanoscale Al phase was formed with a crystallographic orientation relationship with the surrounding Si phase: (111)<sub>Si</sub>//(111)<sub>Al</sub> and [1<span><math><mover><mn>1</mn><mo>¯</mo></mover></math></span>0]<sub>Si</sub>//[1<span><math><mover><mn>1</mn><mo>¯</mo></mover></math></span>0]<sub>Al</sub>. The formation of Al nanoprecipitates was attributed to an interplay between non-equilibrium solidification, wherein excess Al was dissolved in the Si particles, and the subsequent decomposition of the supersaturated Si phase during high-temperature exposure owing to the preheating procedure. To the best of our knowledge, such formation of Al nanoparticles has not been reported in AlSi10Mg produced through conventional processing or LB-PBF. Thus, the unique thermal history of EB-PBF provides novel opportunities for microstructural evolution, which may be beneficial for the development of novel Al-based alloys.</p></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"10 ","pages":"Article 100213"},"PeriodicalIF":0.0,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772369024000227/pdfft?md5=590e92cadc7a00d0e82f6b55f12b83ee&pid=1-s2.0-S2772369024000227-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140822995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-24DOI: 10.1016/j.addlet.2024.100209
Saptarshi Mukherjee, Johanna Schwartz, Emeraldo Baluyot, Tammy Chang, Joseph W. Tringe, Christopher M. Spadaccini, Maxim Shusteff
Visible light-based volumetric additive manufacturing (VAM) technology has recently enabled rapid 3D printing of optically transparent resins in a single step. There is now strong interest in extending the design space of VAM to include opaque, scattering and composite materials. Microwave energy can penetrate more deeply than visible light into a broader family of materials. For microwaves to be useful for VAM, however it is necessary to have a fundamental understanding of material dielectric properties, microwave field propagation and localization. Here we present a multi-physics microwave beam formed-thermal diffusion model that addresses these needs. The model demonstrates its ability to optimize power delivery and curing time to obtain better thermal control. We validate the model with a proof-of-concept single-antenna experimental system operating at 10 GHz that is able to cure a wide variety of materials, including both optically translucent and opaque epoxy resins loaded with conductive additives with a minimum curing spot of 5 mm. While available microwave hardware operating at 40 Watt power cures the resins in 2.5 min, the model estimates the ability to cure in as less as 6 s at 1 Kilowatt power levels. This computational model and experiments lay the foundation for a future multi-waveguide microwave-based VAM system.
{"title":"Towards microwave volumetric additive manufacturing: Generation of a computational multi-physics model for localized curing","authors":"Saptarshi Mukherjee, Johanna Schwartz, Emeraldo Baluyot, Tammy Chang, Joseph W. Tringe, Christopher M. Spadaccini, Maxim Shusteff","doi":"10.1016/j.addlet.2024.100209","DOIUrl":"10.1016/j.addlet.2024.100209","url":null,"abstract":"<div><p>Visible light-based volumetric additive manufacturing (VAM) technology has recently enabled rapid 3D printing of optically transparent resins in a single step. There is now strong interest in extending the design space of VAM to include opaque, scattering and composite materials. Microwave energy can penetrate more deeply than visible light into a broader family of materials. For microwaves to be useful for VAM, however it is necessary to have a fundamental understanding of material dielectric properties, microwave field propagation and localization. Here we present a multi-physics microwave beam formed-thermal diffusion model that addresses these needs. The model demonstrates its ability to optimize power delivery and curing time to obtain better thermal control. We validate the model with a proof-of-concept single-antenna experimental system operating at 10 GHz that is able to cure a wide variety of materials, including both optically translucent and opaque epoxy resins loaded with conductive additives with a minimum curing spot of 5 mm. While available microwave hardware operating at 40 Watt power cures the resins in 2.5 min, the model estimates the ability to cure in as less as 6 s at 1 Kilowatt power levels. This computational model and experiments lay the foundation for a future multi-waveguide microwave-based VAM system.</p></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"10 ","pages":"Article 100209"},"PeriodicalIF":0.0,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772369024000185/pdfft?md5=7b4fe11a7295609c23c72d714fda3af6&pid=1-s2.0-S2772369024000185-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140762365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-23DOI: 10.1016/j.addlet.2024.100216
C.A. Biffi , C. Soyarslan , J. Fiocchi , C. Bregoli , A. du Plessis , A. Tuissi , M. Mehrpouya
Additive manufacturing has revolutionized the creation of complex and intrinsic structures, offering tailored designs for enhanced product performance across various applications. Architected cellular or lattice structures exemplify this innovation, customizable for specific mechanical or functional requirements, boasting advantages such as reduced mass, heightened load-bearing capabilities, and superior energy absorption. Nonetheless, their single-use limitation arises from plastic deformation resulting from localized yield damage or plastic buckling. Incorporating NiTi shape memory alloys (SMAs) presents a solution, enabling structures to recover their original shape post-unloading. In this study, an NiTi architected metastructure, featuring auxetic behavior and a negative Poisson's ratio, was designed and fabricated via laser powder bed fusion (LPBF). The samples exhibit promising superelastic performance with recoverable deformation strains at room temperature. Comprehensive characterization processes evaluated the functional performance of the fabricated metastructures. The metastructure geometry promoted microstructure formation primarily along the wall thickness. Cycling compression tests, conducted at three applied force levels, demonstrated stable cyclic behavior with up to 3.8 % reversible deformation strain, devoid of plastic buckling or yielding damage. Furthermore, the NiTi metastructures displayed robust energy absorption capacity and damping behavior, underscoring their potential for reusable energy dissipators in various industries including aerospace, automotive, construction, and etc.
{"title":"Additive manufacturing of NiTi architected metamaterials","authors":"C.A. Biffi , C. Soyarslan , J. Fiocchi , C. Bregoli , A. du Plessis , A. Tuissi , M. Mehrpouya","doi":"10.1016/j.addlet.2024.100216","DOIUrl":"10.1016/j.addlet.2024.100216","url":null,"abstract":"<div><p>Additive manufacturing has revolutionized the creation of complex and intrinsic structures, offering tailored designs for enhanced product performance across various applications. Architected cellular or lattice structures exemplify this innovation, customizable for specific mechanical or functional requirements, boasting advantages such as reduced mass, heightened load-bearing capabilities, and superior energy absorption. Nonetheless, their single-use limitation arises from plastic deformation resulting from localized yield damage or plastic buckling. Incorporating NiTi shape memory alloys (SMAs) presents a solution, enabling structures to recover their original shape post-unloading. In this study, an NiTi architected metastructure, featuring auxetic behavior and a negative Poisson's ratio, was designed and fabricated via laser powder bed fusion (LPBF). The samples exhibit promising superelastic performance with recoverable deformation strains at room temperature. Comprehensive characterization processes evaluated the functional performance of the fabricated metastructures. The metastructure geometry promoted microstructure formation primarily along the wall thickness. Cycling compression tests, conducted at three applied force levels, demonstrated stable cyclic behavior with up to 3.8 % reversible deformation strain, devoid of plastic buckling or yielding damage. Furthermore, the NiTi metastructures displayed robust energy absorption capacity and damping behavior, underscoring their potential for reusable energy dissipators in various industries including aerospace, automotive, construction, and etc.</p></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"10 ","pages":"Article 100216"},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772369024000252/pdfft?md5=becaff9c5c89736f5ba46208445a2866&pid=1-s2.0-S2772369024000252-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140774431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.1016/j.addlet.2024.100206
Brenda Juliet Martins Freitas , Guilherme Yuuki Koga , Siegfried Arneitz , Claudemiro Bolfarini , Sergio de Traglia Amancio-Filho
Boron has almost null solubility in iron, and its addition to stainless steels leads to the formation of hard borides, beneficial for increasing the wear resistance. However, these boron-containing steels have poor printability, with the occurrence of pronounced cracking, high porosity and risk of delamination. In this work, Box-Behnken design coupled with analysis of variance (ANOVA) was used to optimize the LPBF (Laser Powder Bed Fusion) processing parameters of a highly boron-alloyed stainless steel reinforced with a boride network. The proposed models demonstrated to be accurate in determine the porosity percentage for the studied alloys, in which the laser power and scanning speed play the main role in the alloys’ densification, and absence of extensive defects. These results indicate that the use of design of experiments tools is essential to produce defect-free boron-modified stainless steel specimens with a relatively low number of experiments, identifying a narrow optimized processing window to build bulk composite materials.
{"title":"Optimizing LPBF-parameters by Box-Behnken design for printing crack-free and dense high-boron alloyed stainless steel parts","authors":"Brenda Juliet Martins Freitas , Guilherme Yuuki Koga , Siegfried Arneitz , Claudemiro Bolfarini , Sergio de Traglia Amancio-Filho","doi":"10.1016/j.addlet.2024.100206","DOIUrl":"https://doi.org/10.1016/j.addlet.2024.100206","url":null,"abstract":"<div><p>Boron has almost null solubility in iron, and its addition to stainless steels leads to the formation of hard borides, beneficial for increasing the wear resistance. However, these boron-containing steels have poor printability, with the occurrence of pronounced cracking, high porosity and risk of delamination. In this work, Box-Behnken design coupled with analysis of variance (ANOVA) was used to optimize the LPBF (Laser Powder Bed Fusion) processing parameters of a highly boron-alloyed stainless steel reinforced with a boride network. The proposed models demonstrated to be accurate in determine the porosity percentage for the studied alloys, in which the laser power and scanning speed play the main role in the alloys’ densification, and absence of extensive defects. These results indicate that the use of design of experiments tools is essential to produce defect-free boron-modified stainless steel specimens with a relatively low number of experiments, identifying a narrow optimized processing window to build bulk composite materials.</p></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"9 ","pages":"Article 100206"},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S277236902400015X/pdfft?md5=3f91a5baca22ab813f4f7fd2c8ce57ac&pid=1-s2.0-S277236902400015X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140350844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}