The demand for advanced materials has driven innovation in titanium alloy design, particularly in the aerospace, automotive, and biomedical sectors. Additive manufacturing (AM) enables the construction of multi-material structures, offering potential improvements in mechanical properties such as wear resistance and high-temperature capabilities, thus extending the service life of components such as Ti6Al4V. Directed energy deposition (DED)-based metal AM was used to manufacture radial multi-material structures with a Ti6Al4V (Ti64) core and a Ti6Al4V-5 wt.% B4C composite outer layer. X-ray diffraction analysis and microstructural observation suggest that distinct B4C particles are strongly attached to the Ti6Al4V matrix. The addition of B4C increased the average hardness from 313 HV for Ti6Al4V to 538 HV for the composites. The addition of 5 wt.% B4C in Ti6Al4V increased the average compressive yield strength (YS) to 1440 MPa from 972 MPa for the control Ti6Al4V, i.e., >48% increase without any significant change in the elastic modulus. The radial multi-material structures did not exhibit any changes in the compressive modulus compared to Ti6Al4V but displayed an increase in the average compressive YS to 1422 MPa, i.e., >45% higher compared to Ti6Al4V. Microstructural characterization revealed a smooth transition from the pure Ti6Al4V at the core to the Ti64-B4C composite outer layer. No interfacial failure was observed during compressive deformation, indicating a strong metallurgical bonding during multi-material radial composite processing. Our results demonstrated that a significant improvement in mechanical properties can be achieved in one AM build operation through designing innovative multi-material structures using DED-based AM.
{"title":"Multi-material structures of Ti6Al4V and Ti6Al4V-B4C through directed energy deposition-based additive manufacturing","authors":"Nathaniel W. Zuckschwerdt, Amit Bandyopadhyay","doi":"10.36922/msam.3571","DOIUrl":"https://doi.org/10.36922/msam.3571","url":null,"abstract":"The demand for advanced materials has driven innovation in titanium alloy design, particularly in the aerospace, automotive, and biomedical sectors. Additive manufacturing (AM) enables the construction of multi-material structures, offering potential improvements in mechanical properties such as wear resistance and high-temperature capabilities, thus extending the service life of components such as Ti6Al4V. Directed energy deposition (DED)-based metal AM was used to manufacture radial multi-material structures with a Ti6Al4V (Ti64) core and a Ti6Al4V-5 wt.% B4C composite outer layer. X-ray diffraction analysis and microstructural observation suggest that distinct B4C particles are strongly attached to the Ti6Al4V matrix. The addition of B4C increased the average hardness from 313 HV for Ti6Al4V to 538 HV for the composites. The addition of 5 wt.% B4C in Ti6Al4V increased the average compressive yield strength (YS) to 1440 MPa from 972 MPa for the control Ti6Al4V, i.e., >48% increase without any significant change in the elastic modulus. The radial multi-material structures did not exhibit any changes in the compressive modulus compared to Ti6Al4V but displayed an increase in the average compressive YS to 1422 MPa, i.e., >45% higher compared to Ti6Al4V. Microstructural characterization revealed a smooth transition from the pure Ti6Al4V at the core to the Ti64-B4C composite outer layer. No interfacial failure was observed during compressive deformation, indicating a strong metallurgical bonding during multi-material radial composite processing. Our results demonstrated that a significant improvement in mechanical properties can be achieved in one AM build operation through designing innovative multi-material structures using DED-based AM.","PeriodicalId":422581,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"46 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141663727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yiting Huang, Qi Zhu, Haofan Liu, Ya Ren, Li Zhang, Maling Gou
Electrodes serve as essential tools for both acquiring and stimulating electrical signals, pivotal in monitoring human health through electrophysiological signals and playing a significant role in disease management and treatment. Notably, Young’s modulus of flexible electrodes is similar to that of tissues and organs, thereby avoiding tissue or organ damage arising from mechanical mismatch. Thus, flexible electrodes become the fundamental devices for ensuring the stable, long-term acquisition of electrical signals and delivering reversed electrical stimulation to guide disease treatment. Reducing the size of flexible electrodes and increasing the number of electrode channels are significant for improving the sensitivity and accuracy of signal acquisition. In comparison to traditional manufacturing methods, 3D printing technology is able to fabricate products with higher resolution at a much faster speed. It is customizable and provides a novel approach for preparing flexible electrodes. Many conductive materials have been developed and applied to prepare flexible electrodes, and some have been integrated into 3D printing techniques, driving forward the development of 3D-printed flexible electrodes in medical fields. This article reviews recent research advances concerning the combination of these materials with 3D printing technology to prepare flexible electrodes and categorizes the materials into four main groups, namely metallic materials, carbon-based materials, conductive polymers, and other materials. In addition, we outline the future directions regarding the application of 3D-printed flexible electrodes in clinical research and medical translation.
{"title":"Current materials for 3D-printed flexible medical electrodes","authors":"Yiting Huang, Qi Zhu, Haofan Liu, Ya Ren, Li Zhang, Maling Gou","doi":"10.36922/msam.2084","DOIUrl":"https://doi.org/10.36922/msam.2084","url":null,"abstract":"Electrodes serve as essential tools for both acquiring and stimulating electrical signals, pivotal in monitoring human health through electrophysiological signals and playing a significant role in disease management and treatment. Notably, Young’s modulus of flexible electrodes is similar to that of tissues and organs, thereby avoiding tissue or organ damage arising from mechanical mismatch. Thus, flexible electrodes become the fundamental devices for ensuring the stable, long-term acquisition of electrical signals and delivering reversed electrical stimulation to guide disease treatment. Reducing the size of flexible electrodes and increasing the number of electrode channels are significant for improving the sensitivity and accuracy of signal acquisition. In comparison to traditional manufacturing methods, 3D printing technology is able to fabricate products with higher resolution at a much faster speed. It is customizable and provides a novel approach for preparing flexible electrodes. Many conductive materials have been developed and applied to prepare flexible electrodes, and some have been integrated into 3D printing techniques, driving forward the development of 3D-printed flexible electrodes in medical fields. This article reviews recent research advances concerning the combination of these materials with 3D printing technology to prepare flexible electrodes and categorizes the materials into four main groups, namely metallic materials, carbon-based materials, conductive polymers, and other materials. In addition, we outline the future directions regarding the application of 3D-printed flexible electrodes in clinical research and medical translation.","PeriodicalId":422581,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"24 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139009463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Auxetic structures have negative Poisson’s ratios (NPR). Due to the unique deformation mechanism, auxetic structures possess extraordinary mechanical properties, such as indentation resistance, shear resistance, fracture toughness, and energy absorption capability. However, the stiffness and load-bearing capacity are the weak points for auxetic structures. 3D printing of continuous fiber-reinforced composite enables the fabrication of lightweight and highly stiff complex structures, providing a perfect manufacturing method to remedy the shortcomings of auxetic structures. This work investigated the mechanical properties of 3D-printed continuous fiber-reinforced composite auxetic structures. In this study, we utilized continuous fiber-reinforced composite 3D printing to fabricate two types of auxetic structures. The fiber path configurations were varied among the test specimens to explore the effect of fiber distribution on mechanical properties. A uniaxial tensile test was performed to evaluate the tensile properties and Poisson’s ratio of continuous fiber-reinforced composite auxetic structures. Results showed that the tensile modulus and strength have been dramatically improved with a minor mass increase. The auxetic behavior can be strengthened by properly allocating the reinforcing fibers. However, the addition of continuous fiber led to different performances on the selected auxetic structures. In summary, two out of the five specimens demonstrated simultaneous improvements in stiffness, strength, and auxeticity across the conducted tests.
{"title":"An experimental study on 3D-printed continuous fiber-reinforced composite auxetic structures","authors":"Peiqing Liu, Jikai Liu","doi":"10.36922/msam.2159","DOIUrl":"https://doi.org/10.36922/msam.2159","url":null,"abstract":"Auxetic structures have negative Poisson’s ratios (NPR). Due to the unique deformation mechanism, auxetic structures possess extraordinary mechanical properties, such as indentation resistance, shear resistance, fracture toughness, and energy absorption capability. However, the stiffness and load-bearing capacity are the weak points for auxetic structures. 3D printing of continuous fiber-reinforced composite enables the fabrication of lightweight and highly stiff complex structures, providing a perfect manufacturing method to remedy the shortcomings of auxetic structures. This work investigated the mechanical properties of 3D-printed continuous fiber-reinforced composite auxetic structures. In this study, we utilized continuous fiber-reinforced composite 3D printing to fabricate two types of auxetic structures. The fiber path configurations were varied among the test specimens to explore the effect of fiber distribution on mechanical properties. A uniaxial tensile test was performed to evaluate the tensile properties and Poisson’s ratio of continuous fiber-reinforced composite auxetic structures. Results showed that the tensile modulus and strength have been dramatically improved with a minor mass increase. The auxetic behavior can be strengthened by properly allocating the reinforcing fibers. However, the addition of continuous fiber led to different performances on the selected auxetic structures. In summary, two out of the five specimens demonstrated simultaneous improvements in stiffness, strength, and auxeticity across the conducted tests.","PeriodicalId":422581,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"54 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139009708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Orthopedic bone plates, traditionally made from materials such as stainless steel or titanium alloy, have been pivotal in treating fractures. However, the disparity in modulus between these metals and natural bone leads to challenges, especially stress shielding, which can hinder optimal healing and cause issues such as bone resorption. In addition, the increase in complex fractures due to osteoporosis and demographic changes also points to the limitations of standard bone plates. This evolving landscape underscores the growing need for patient-specific solutions. This review delves into the advantages and challenges concerning the material choice, design, and production processes for the additive manufacturing (AM) of bone plates. AM offers the potential to customize bone plates using detailed computerized tomography scans or topology optimization, paving the way for unparalleled customization and potentially more effective bone regeneration. However, the intricacies of AM, from choosing the right materials to final production, add layers of complexity. An innovative methodology in the field of laser-metal Additive Manufacturing, known as Material-Structure-Performance Integrated AM (MSPI-AM), is at the forefront of tackling existing challenges, with the goal of enhancing the overall process in this domain. This strategy seamlessly blends material properties, structural components, and functional performance. Enriched by the analytical capabilities of artificial intelligence, this comprehensive method aims to enhance the AM process. It envisions a future where orthopedic treatments are not just functional but also are personalized masterpieces that reflect individual patient needs and address a variety of fracture scenarios.
骨科骨板传统上由不锈钢或钛合金等材料制成，在治疗骨折方面起着举足轻重的作用。然而，这些金属与天然骨骼之间的模量差异带来了挑战，尤其是应力屏蔽，这会阻碍最佳愈合并导致骨吸收等问题。此外，骨质疏松症和人口结构变化导致复杂骨折的增加，也说明了标准骨板的局限性。这种不断变化的情况凸显了对患者特定解决方案的需求日益增长。本综述深入探讨了骨板增材制造（AM）在材料选择、设计和生产工艺方面的优势和挑战。AM 可通过详细的计算机断层扫描或拓扑优化来定制骨板，为无与伦比的定制和更有效的骨再生铺平道路。然而，从选择合适的材料到最终生产，AM 技术的复杂性层出不穷。激光金属增材制造领域的一种创新方法，即材料-结构-性能一体化增材制造（MSPI-AM），正处于应对现有挑战的最前沿，其目标是提高该领域的整体工艺水平。这一战略将材料特性、结构组件和功能性能完美地融合在一起。这种综合方法借助人工智能的分析能力，旨在增强 AM 工艺。在它的设想中，未来的骨科治疗不仅是功能性的，而且是个性化的杰作，能反映患者的个性化需求，并能解决各种骨折情况。
{"title":"Metal additive manufacturing of orthopedic bone plates: An overview","authors":"Weiting Xu, Aydin Nassehi, Fengyuan Liu","doi":"10.36922/msam.2113","DOIUrl":"https://doi.org/10.36922/msam.2113","url":null,"abstract":"Orthopedic bone plates, traditionally made from materials such as stainless steel or titanium alloy, have been pivotal in treating fractures. However, the disparity in modulus between these metals and natural bone leads to challenges, especially stress shielding, which can hinder optimal healing and cause issues such as bone resorption. In addition, the increase in complex fractures due to osteoporosis and demographic changes also points to the limitations of standard bone plates. This evolving landscape underscores the growing need for patient-specific solutions. This review delves into the advantages and challenges concerning the material choice, design, and production processes for the additive manufacturing (AM) of bone plates. AM offers the potential to customize bone plates using detailed computerized tomography scans or topology optimization, paving the way for unparalleled customization and potentially more effective bone regeneration. However, the intricacies of AM, from choosing the right materials to final production, add layers of complexity. An innovative methodology in the field of laser-metal Additive Manufacturing, known as Material-Structure-Performance Integrated AM (MSPI-AM), is at the forefront of tackling existing challenges, with the goal of enhancing the overall process in this domain. This strategy seamlessly blends material properties, structural components, and functional performance. Enriched by the analytical capabilities of artificial intelligence, this comprehensive method aims to enhance the AM process. It envisions a future where orthopedic treatments are not just functional but also are personalized masterpieces that reflect individual patient needs and address a variety of fracture scenarios.","PeriodicalId":422581,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"457 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139011161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Titanium is a widely used metal in biomedical applications due to its low toxicity, but its mechanical properties need to be tailored for different applications. Efforts are called for to search for effective and yet non-toxic elements to be alloyed with Ti to improve its strength. Fitting in this category, Mn and Mo are two such alloying elements. In this study, Ti-6Mn-4Mo alloy was manufactured by laser-directed energy deposition (DED) through in situ alloying of Ti, Mn, and Mo elemental powders. This study was intended to not only demonstrate for the first time the printability of the Ti-Mn-Mo ternary system by laser DED but also investigate the basic mechanical properties and corrosion resistance of the obtained alloy. Under the as-built condition, the alloy consisted mainly of ß phase, while after heat treatment it was transformed into α phase. The average ultimate tensile strength under as-built condition was 706.0 MPa, lower than similar alloys from conventional methods. However, the average hardness reached 421.1 HV for the as-built condition, much higher than the similar alloys made through conventional methods. On the other hand, the corrosion resistance of the obtained alloy was found to be relatively low compared to similar alloys produced with traditional methods. In addition, heat treatment was not able to significantly change the tensile properties or the corrosion resistance. In essence, the exploratory study indicates that the DED-produced Ti-Mn-Mo alloy could be deposited without cracks and major voids, and shows that its high hardness and modulus are attractive to applications for high wear resistance. However, further investigation is needed to improve strength, ductility, and corrosion resistance of the alloy.
{"title":"An exploratory study on biocompatible Ti-6Mn-4Mo alloy manufactured by directed energy deposition","authors":"Roman Savinov, Yachao Wang, Jing Shi","doi":"10.36922/msam.2180","DOIUrl":"https://doi.org/10.36922/msam.2180","url":null,"abstract":"Titanium is a widely used metal in biomedical applications due to its low toxicity, but its mechanical properties need to be tailored for different applications. Efforts are called for to search for effective and yet non-toxic elements to be alloyed with Ti to improve its strength. Fitting in this category, Mn and Mo are two such alloying elements. In this study, Ti-6Mn-4Mo alloy was manufactured by laser-directed energy deposition (DED) through in situ alloying of Ti, Mn, and Mo elemental powders. This study was intended to not only demonstrate for the first time the printability of the Ti-Mn-Mo ternary system by laser DED but also investigate the basic mechanical properties and corrosion resistance of the obtained alloy. Under the as-built condition, the alloy consisted mainly of ß phase, while after heat treatment it was transformed into α phase. The average ultimate tensile strength under as-built condition was 706.0 MPa, lower than similar alloys from conventional methods. However, the average hardness reached 421.1 HV for the as-built condition, much higher than the similar alloys made through conventional methods. On the other hand, the corrosion resistance of the obtained alloy was found to be relatively low compared to similar alloys produced with traditional methods. In addition, heat treatment was not able to significantly change the tensile properties or the corrosion resistance. In essence, the exploratory study indicates that the DED-produced Ti-Mn-Mo alloy could be deposited without cracks and major voids, and shows that its high hardness and modulus are attractive to applications for high wear resistance. However, further investigation is needed to improve strength, ductility, and corrosion resistance of the alloy.","PeriodicalId":422581,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"67 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139011207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Sánchez, Augusto G. Nobre, J. A. E. Martinez, João F. Campanaro, Vitor M. L. Vargas
The current work aimed to produce acrylonitrile butadiene styrene (ABS) filament with cellulose microfibers additive for three-dimensional (3D)-printing and perform initial mechanical characterizations. 3D printing is a Fourth Industrial Revolution enabling technology aimed at smart production process. Cellulose is an organic molecule extremely common in nature with potential application as materials reinforcement. Highly crystalline cellulose microfibers were extracted from certified Eucalyptus grandis wood. E. grandis is a species native to Australia, but widely used in reforestation initiatives on a global scale. Cellulose microfiber was inserted at 0.5% in weight into commercial ABS to produce filaments for 3D printing. After the production of pure ABS and ABS with microcellulose filaments, specimens were printed using fused deposition modeling for traction, flexion, and impact tests, in addition to measuring the melt flow index. The results between the two materials were compared, revealing that most of the mechanical properties were similar within the limits of experimental errors, but the strain at break in the traction test was improved in microfibers composite, in addition to an improvement in the elastic modulus and stress at break in flexion test. On melt flow index measurement, both materials were found to be considerably more fluid than the polymer from commercial producer sources. This is an indication that the ABS degraded throughout the process, losing molar mass. However, our work demonstrated that it is possible to add highly crystalline cellulose microfibers to ABS to form filaments for 3D printing.
{"title":"Considerations about highly crystalline cellulose microfiber additive from Eucalyptus grandis for 3D-printing acrylonitrile butadiene styrene filament","authors":"M. Sánchez, Augusto G. Nobre, J. A. E. Martinez, João F. Campanaro, Vitor M. L. Vargas","doi":"10.36922/msam.1000","DOIUrl":"https://doi.org/10.36922/msam.1000","url":null,"abstract":"The current work aimed to produce acrylonitrile butadiene styrene (ABS) filament with cellulose microfibers additive for three-dimensional (3D)-printing and perform initial mechanical characterizations. 3D printing is a Fourth Industrial Revolution enabling technology aimed at smart production process. Cellulose is an organic molecule extremely common in nature with potential application as materials reinforcement. Highly crystalline cellulose microfibers were extracted from certified Eucalyptus grandis wood. E. grandis is a species native to Australia, but widely used in reforestation initiatives on a global scale. Cellulose microfiber was inserted at 0.5% in weight into commercial ABS to produce filaments for 3D printing. After the production of pure ABS and ABS with microcellulose filaments, specimens were printed using fused deposition modeling for traction, flexion, and impact tests, in addition to measuring the melt flow index. The results between the two materials were compared, revealing that most of the mechanical properties were similar within the limits of experimental errors, but the strain at break in the traction test was improved in microfibers composite, in addition to an improvement in the elastic modulus and stress at break in flexion test. On melt flow index measurement, both materials were found to be considerably more fluid than the polymer from commercial producer sources. This is an indication that the ABS degraded throughout the process, losing molar mass. However, our work demonstrated that it is possible to add highly crystalline cellulose microfibers to ABS to form filaments for 3D printing.","PeriodicalId":422581,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"329 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115968302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhenhui Lu, Sandra Leong Lai San, M. Tan, J. An, Yi Zhang, C. Chua
Selective laser melting (SLM) is a promising additive manufacturing method that falls under the category of powder bed fusion (PBF) technology. It has many advantages such as material versatility, efficiency, and the ability to print complex parts without additional machining. However, its surface quality and fatigue properties have been found to be inferior to traditional manufacturing methods. Process-related defects such as pores, incomplete fusion, and un-melted powders give rise to areas of stress concentrations, which lead to mechanical inferiority such as poor fatigue strength. This study aims to investigate and optimize the printing process parameters for Ti6Al4V fabricated by SLM to reduce process-related defects and to investigate their relative density, tensile, and fatigue properties. Ti6Al4V specimens were printed in both 30- and 130-μm layer thicknesses using SLM280 and subjected to tensile and fatigue testing according to ASTM standards. The relative density of Ti6Al4V samples built by 30-µm layer thickness is 99.97 ± 0.02 % (n = 8). The relative density of Ti6Al4V samples built by 130-µm layer thickness is 99.96 ± 0.02 % (n = 8). The average ultimate tensile strength (UTS) of specimens with 30-μm layer thickness is 1152.8 ± 23.8 MPa (n = 4). The average UTS of specimens with 130-μm layer thickness is 1075.5 ± 46.8 MPa (n = 4). S/N curve of the fatigue performance of Ti6Al4V samples printed by 30-μm layer thickness was also obtained. Possible factors impacting the tensile property of SLM-produced parts, such as layer thickness, build orientation, and post-process, are discussed in this paper. Furthermore, crack propagation and surface quality were observed using optical microscopes, laser scanning microscopes, and scanning electron microscopes. The findings of this study will contribute to the improvement of SLM-printed Ti6Al4V parts, which can be potentially applied in the aerospace industry, where fatigue strength is critical to ensuring safety.
{"title":"Preliminary investigation on tensile and fatigue properties of Ti6Al4V manufactured by selected laser melting","authors":"Zhenhui Lu, Sandra Leong Lai San, M. Tan, J. An, Yi Zhang, C. Chua","doi":"10.36922/msam.0912","DOIUrl":"https://doi.org/10.36922/msam.0912","url":null,"abstract":"Selective laser melting (SLM) is a promising additive manufacturing method that falls under the category of powder bed fusion (PBF) technology. It has many advantages such as material versatility, efficiency, and the ability to print complex parts without additional machining. However, its surface quality and fatigue properties have been found to be inferior to traditional manufacturing methods. Process-related defects such as pores, incomplete fusion, and un-melted powders give rise to areas of stress concentrations, which lead to mechanical inferiority such as poor fatigue strength. This study aims to investigate and optimize the printing process parameters for Ti6Al4V fabricated by SLM to reduce process-related defects and to investigate their relative density, tensile, and fatigue properties. Ti6Al4V specimens were printed in both 30- and 130-μm layer thicknesses using SLM280 and subjected to tensile and fatigue testing according to ASTM standards. The relative density of Ti6Al4V samples built by 30-µm layer thickness is 99.97 ± 0.02 % (n = 8). The relative density of Ti6Al4V samples built by 130-µm layer thickness is 99.96 ± 0.02 % (n = 8). The average ultimate tensile strength (UTS) of specimens with 30-μm layer thickness is 1152.8 ± 23.8 MPa (n = 4). The average UTS of specimens with 130-μm layer thickness is 1075.5 ± 46.8 MPa (n = 4). S/N curve of the fatigue performance of Ti6Al4V samples printed by 30-μm layer thickness was also obtained. Possible factors impacting the tensile property of SLM-produced parts, such as layer thickness, build orientation, and post-process, are discussed in this paper. Furthermore, crack propagation and surface quality were observed using optical microscopes, laser scanning microscopes, and scanning electron microscopes. The findings of this study will contribute to the improvement of SLM-printed Ti6Al4V parts, which can be potentially applied in the aerospace industry, where fatigue strength is critical to ensuring safety.","PeriodicalId":422581,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116565985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Luhao Yuan, D. Gu, Kaijie Lin, Xinyu Shi, He Liu, Han Zhang, Xin Liu, Jianfeng Sun
After millions of years of evolution, nature has evolved materials and structures with excellent performance and has provided a source of inspiration for designing high-performance structures. The bionic lobster eye structure (BLES) is a typical example of imitating the good light-focusing performance of lobster eyes. Here, the BLESs with different structural parameters were designed and fabricated by laser powder bed fusion (LPBF). The experimental results demonstrated that the highest relative density of 99.98% can be obtained at a laser power of 400 W and scanning speed of 2200 mm/s, and the upper profile in each microchannel formed under this parameter was regular. All BLESs exhibited a bright central focal facula with a diffuse background on the focus plate. The light-collecting ability of LPBF-processed BLES was decreased with the increase of the upper width of microchannel (UWM), and samples with a small UWM (1.0 mm and 1.25 mm) had a good light-focusing ability. The light intensity on the analysis surface increased as the analysis surface was away from the center of BLES (optical axis), which was detrimental to the optical focusing performance. The BLES could potentially be applied to satellites to improve the efficiency of light collection of the satellite while reducing the probability of being detected.
{"title":"Laser additive manufacturing of microchannel array structure inspired by lobster eyes: Forming ability and optical focusing performance","authors":"Luhao Yuan, D. Gu, Kaijie Lin, Xinyu Shi, He Liu, Han Zhang, Xin Liu, Jianfeng Sun","doi":"10.36922/msam.0361","DOIUrl":"https://doi.org/10.36922/msam.0361","url":null,"abstract":"After millions of years of evolution, nature has evolved materials and structures with excellent performance and has provided a source of inspiration for designing high-performance structures. The bionic lobster eye structure (BLES) is a typical example of imitating the good light-focusing performance of lobster eyes. Here, the BLESs with different structural parameters were designed and fabricated by laser powder bed fusion (LPBF). The experimental results demonstrated that the highest relative density of 99.98% can be obtained at a laser power of 400 W and scanning speed of 2200 mm/s, and the upper profile in each microchannel formed under this parameter was regular. All BLESs exhibited a bright central focal facula with a diffuse background on the focus plate. The light-collecting ability of LPBF-processed BLES was decreased with the increase of the upper width of microchannel (UWM), and samples with a small UWM (1.0 mm and 1.25 mm) had a good light-focusing ability. The light intensity on the analysis surface increased as the analysis surface was away from the center of BLES (optical axis), which was detrimental to the optical focusing performance. The BLES could potentially be applied to satellites to improve the efficiency of light collection of the satellite while reducing the probability of being detected.","PeriodicalId":422581,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"36 29","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113934225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper proposes novel thin-walled structures inspired by Moore space-filling curves. Nine designs, featuring three fractal hierarchies (1st, 2nd, and 3rd orders) with three different relative densities (20%, 30%, and 40%), were used as cross-sectional configurations of the thin-walled structures. Specimens were manufactured using a material extrusion additive manufacturing technique, fused filament fabrication, with a carbon fiber-reinforced composite. Quasi-static compression tests from in-plane direction were conducted to investigate the influences of fractal hierarchy and relative density on the energy absorption capacity. Finite element models were developed to compare with the experiments and to further explore the 4th order structures. A certain level of compliance and snap-in instability were observed in all the structures. These properties show great potential for such thin-walled structures to absorb more energy by enduring large strain. Among them, the 2nd order structures exhibited the best energy absorption capacity. Furthermore, loading and unloading compression tests were performed on the 2nd and 3rd order structures (relative density of 20%) to evaluate their resilience toward displacement and damages. The residual strain and dissipated energy ratio demonstrated that the 2nd order structure outperformed the 3rd order structure owing to its less compliant feature. The integration of Moore curves with thin-walled structures contributes to great compliance and snap-in instability, offering a new approach to designing lightweight energy absorption structures.
{"title":"Energy absorption and recoverability of Moore space-filling thin-walled structures","authors":"Changlang Wu, V. Nguyen-Van, Phuong Tran","doi":"10.36922/msam.53","DOIUrl":"https://doi.org/10.36922/msam.53","url":null,"abstract":"This paper proposes novel thin-walled structures inspired by Moore space-filling curves. Nine designs, featuring three fractal hierarchies (1st, 2nd, and 3rd orders) with three different relative densities (20%, 30%, and 40%), were used as cross-sectional configurations of the thin-walled structures. Specimens were manufactured using a material extrusion additive manufacturing technique, fused filament fabrication, with a carbon fiber-reinforced composite. Quasi-static compression tests from in-plane direction were conducted to investigate the influences of fractal hierarchy and relative density on the energy absorption capacity. Finite element models were developed to compare with the experiments and to further explore the 4th order structures. A certain level of compliance and snap-in instability were observed in all the structures. These properties show great potential for such thin-walled structures to absorb more energy by enduring large strain. Among them, the 2nd order structures exhibited the best energy absorption capacity. Furthermore, loading and unloading compression tests were performed on the 2nd and 3rd order structures (relative density of 20%) to evaluate their resilience toward displacement and damages. The residual strain and dissipated energy ratio demonstrated that the 2nd order structure outperformed the 3rd order structure owing to its less compliant feature. The integration of Moore curves with thin-walled structures contributes to great compliance and snap-in instability, offering a new approach to designing lightweight energy absorption structures.","PeriodicalId":422581,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127682834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. D. Goh, Xi Huang, Sheng Huang, Jia Li Janessa Thong, Jia Jun Seah, W. Yeong
A database linking process parameters and material properties for additive manufacturing enables the performance of the material to be determined based on the process parameters, which are useful in the design and fabrication stage of a product. The data, however, are often incomplete as each individual research work focused on certain process parameters and material properties due to the wide range of variables available. Imputation of missing data is thus required to complete the material library. In this work, we attempt to collate the data of Ti6Al4V, a popular alloy used in aerospace and biomedical industries, fabricated using powder bed fusion, or commonly known as selective laser melting (SLM). Various imputation techniques of missing data of the SLM Ti6Al4V dataset, such as the k-nearest neighbor (kNN), multivariate imputation by chained equations, and graph imputation neural network (GINN) are investigated in this article. It was observed that kNN performed better in imputing variables related to process parameters, whereas GINN performed better in variables related to material properties. To further improve the quality of imputation, a strategy to use the median of the imputed values obtained from the three models has resulted in significant improvement in terms of the relative mean square error. Self-organizing map was used to visualize the relationship among the process parameters and the material properties.
{"title":"Data imputation strategies for process optimization of laser powder bed fusion of Ti6Al4V using machine learning","authors":"G. D. Goh, Xi Huang, Sheng Huang, Jia Li Janessa Thong, Jia Jun Seah, W. Yeong","doi":"10.36922/msam.50","DOIUrl":"https://doi.org/10.36922/msam.50","url":null,"abstract":"A database linking process parameters and material properties for additive manufacturing enables the performance of the material to be determined based on the process parameters, which are useful in the design and fabrication stage of a product. The data, however, are often incomplete as each individual research work focused on certain process parameters and material properties due to the wide range of variables available. Imputation of missing data is thus required to complete the material library. In this work, we attempt to collate the data of Ti6Al4V, a popular alloy used in aerospace and biomedical industries, fabricated using powder bed fusion, or commonly known as selective laser melting (SLM). Various imputation techniques of missing data of the SLM Ti6Al4V dataset, such as the k-nearest neighbor (kNN), multivariate imputation by chained equations, and graph imputation neural network (GINN) are investigated in this article. It was observed that kNN performed better in imputing variables related to process parameters, whereas GINN performed better in variables related to material properties. To further improve the quality of imputation, a strategy to use the median of the imputed values obtained from the three models has resulted in significant improvement in terms of the relative mean square error. Self-organizing map was used to visualize the relationship among the process parameters and the material properties.","PeriodicalId":422581,"journal":{"name":"Materials Science in Additive Manufacturing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134439632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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