Pub Date : 2024-08-01DOI: 10.1088/1757-899x/1310/1/012020
D Hu, R Biswal, V K Sahu, J W Fellowes, A Zadehkabir, S W Williams, A E Davis
Additive manufacturing (AM) using recycled Ti-6Al-4V (Ti64) feedstock material from wrought waste streams is a novel process that can reduce the overall energy cost and carbon (CO2) footprint when compared to primary-production routes. The potential contamination of recycled feedstock material (e.g. C, O, N and Fe) can affect the microstructure and mechanical properties of the component. In this work, a Ti64 test wall built using wire arc AM (WAAM) was studied, where the top half only was contaminated by N through the shielding gas during deposition. This allowed a direct comparison of Ti64 WAAM material with high and low N content, deposited under otherwise identical conditions, to replicate the worst-case scenario of N contamination from using recycled swarf. The hardness of the N-contaminated section was found to be 25% higher than the uncontaminated section of the wall, demonstrating the N solid solution strengthening in Ti64. The room temperature transformed microstructure was found to have a 25% coarser α-lath thickness, which was proposed to be an effect of the AM cyclical heating and increasing of the β-transus temperature due to a higher level of N. Additionally, the outer layer of the N-contaminated sample section was found to have a refined parent β grain structure.
使用从锻造废料流中回收的钛-6Al-4V（Ti64）原料进行快速成型制造（AM）是一种新型工艺，与初级生产工艺相比，可降低总体能源成本和碳足迹（CO2）。回收原料材料的潜在污染（如 C、O、N 和 Fe）会影响部件的微观结构和机械性能。在这项工作中，我们研究了使用线弧 AM（WAAM）制造的 Ti64 试验壁，其中只有上半部分在沉积过程中通过屏蔽气体受到 N 污染。这样就可以直接比较在相同条件下沉积的高 N 含量和低 N 含量的 Ti64 WAAM 材料，以复制使用回收废料造成 N 污染的最坏情况。结果发现，N 污染部分的硬度比未受污染部分的硬度高 25%，这证明了 Ti64 中的 N 固溶强化作用。室温转化后的微观结构发现，α-板条厚度粗了 25%，这可能是 AM 循环加热以及由于 N 含量较高而使β-横截面温度升高的结果。
{"title":"On the chemical composition, microstructure and mechanical properties of a Nitrogen-contaminated Ti-6Al-4V component built by Wire-Arc Additive Manufacturing","authors":"D Hu, R Biswal, V K Sahu, J W Fellowes, A Zadehkabir, S W Williams, A E Davis","doi":"10.1088/1757-899x/1310/1/012020","DOIUrl":"https://doi.org/10.1088/1757-899x/1310/1/012020","url":null,"abstract":"Additive manufacturing (AM) using recycled Ti-6Al-4V (Ti64) feedstock material from wrought waste streams is a novel process that can reduce the overall energy cost and carbon (CO<sub>2</sub>) footprint when compared to primary-production routes. The potential contamination of recycled feedstock material (e.g. C, O, N and Fe) can affect the microstructure and mechanical properties of the component. In this work, a Ti64 test wall built using wire arc AM (WAAM) was studied, where the top half only was contaminated by N through the shielding gas during deposition. This allowed a direct comparison of Ti64 WAAM material with high and low N content, deposited under otherwise identical conditions, to replicate the worst-case scenario of N contamination from using recycled swarf. The hardness of the N-contaminated section was found to be 25% higher than the uncontaminated section of the wall, demonstrating the N solid solution strengthening in Ti64. The room temperature transformed microstructure was found to have a 25% coarser α-lath thickness, which was proposed to be an effect of the AM cyclical heating and increasing of the β-transus temperature due to a higher level of N. Additionally, the outer layer of the N-contaminated sample section was found to have a refined parent β grain structure.","PeriodicalId":14483,"journal":{"name":"IOP Conference Series: Materials Science and Engineering","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187416","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}
Pub Date : 2024-08-01DOI: 10.1088/1757-899x/1312/1/012013
Wouter Remmerie, Nikola Majksner
This paper presents two open-source tools to increase precision and automate CFD simulations in OpenFOAM. The first is an adaptive mesh refinement method which uses custom field properties to refine both volume and surface cells. The second is a method to detect convergence and dynamically size the length of the averaging window to obtain reliable averaged values.
{"title":"Open source tools for OpenFOAM - Adaptive mesh refinement and convergence detection","authors":"Wouter Remmerie, Nikola Majksner","doi":"10.1088/1757-899x/1312/1/012013","DOIUrl":"https://doi.org/10.1088/1757-899x/1312/1/012013","url":null,"abstract":"This paper presents two open-source tools to increase precision and automate CFD simulations in OpenFOAM. The first is an adaptive mesh refinement method which uses custom field properties to refine both volume and surface cells. The second is a method to detect convergence and dynamically size the length of the averaging window to obtain reliable averaged values.","PeriodicalId":14483,"journal":{"name":"IOP Conference Series: Materials Science and Engineering","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187310","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}
Pub Date : 2024-08-01DOI: 10.1088/1757-899x/1312/1/012001
Eric Segalerba, Emanuele Gallorini, Maurizio Quadrio, Jan Pralits
Nasal Breathing Difficulties (NBD) consist of pathologies which are difficult to diagnose, heal and affect a high percentage of the population; the only way to treat these diseases is, most of the times, by surgery but the success rate is not very high since many patients have no relief from it. This should be attributed to the variety of the nose’s functions, which is far more complex than a simple duct to connect the environment to the lungs. CFD is emerging as an innovative approach to study these problems systematically; in this contribution the target is to use a method based on adjoint equations to get senstivity maps whose purpose is to provide surgeons with more informations on which are the regions, inside the nose, to focus on. This work focuses only on the reduction of the pressure drop across the nose, therefore a single objective function is used. Three different frameworks, with two formulations of the continuous adjoint equation method, are compared: in two cases topological sensitivities were used while in the latter the surface sensitivity was evaluated.
{"title":"On the comparison between topological and surface sensitivities for bio-fluid dynamics applications","authors":"Eric Segalerba, Emanuele Gallorini, Maurizio Quadrio, Jan Pralits","doi":"10.1088/1757-899x/1312/1/012001","DOIUrl":"https://doi.org/10.1088/1757-899x/1312/1/012001","url":null,"abstract":"Nasal Breathing Difficulties (NBD) consist of pathologies which are difficult to diagnose, heal and affect a high percentage of the population; the only way to treat these diseases is, most of the times, by surgery but the success rate is not very high since many patients have no relief from it. This should be attributed to the variety of the nose’s functions, which is far more complex than a simple duct to connect the environment to the lungs. CFD is emerging as an innovative approach to study these problems systematically; in this contribution the target is to use a method based on adjoint equations to get senstivity maps whose purpose is to provide surgeons with more informations on which are the regions, inside the nose, to focus on. This work focuses only on the reduction of the pressure drop across the nose, therefore a single objective function is used. Three different frameworks, with two formulations of the continuous adjoint equation method, are compared: in two cases topological sensitivities were used while in the latter the surface sensitivity was evaluated.","PeriodicalId":14483,"journal":{"name":"IOP Conference Series: Materials Science and Engineering","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187345","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}
Pub Date : 2024-08-01DOI: 10.1088/1757-899x/1312/1/012009
Flavio Cesar Cunha Galeazzo, R. Gregor Weiß, Sergey Lesnik, Henrik Rusche, Andreas Ruopp
The performance of OpenFOAM in strong scaling tests on HPC systems with AMD EPYC processors exhibits a pronounced superlinear speedup. Simple test cases show superlinear speedups of over 300%, which significantly impacts the efficient use of computing resources.With the last generation of HPC architectures, a superlinear speedup of about 10% to 20% was well expected and accepted by CFD users [1]. The measured superlinear speedup is much more pronounced and withstands the communication overhead to even larger scales.A detailed performance analysis of OpenFOAM follows, employing various High-Performance Computing (HPC) architectures, including AMD, ARM and Intel systems. The performance metric FVOPS (Finite VOlumes solved Per Second) is introduced to compare the performance of Computational Fluid Dynamics (CFD) applications when varying the grid size, as occurs in a strong scaling test. The achievable FVOPS depends on various factors, including the simulation type, boundary conditions, and especially the grid size of a use case. Analysing FVOPS on a single node level with varying grid size shows a significant difference in performance and cache utilization, which explains the large superlinear speedups seen in the strong scaling tests.Furthermore, FVOPS can be used as a simple benchmark to determine the optimal number of grid elements per rank to simulate a given use case at peak efficiency on a given platform, resulting in time, energy, and cost savings.The FVOPS metric also facilitates the direct comparison between different HPC architectures. The tests using AMD, ARM, and Intel processors show a peak in performance when employing around 10,000 grid elements per core. The presence of a large L3 cache on AMD processors is particularly advantageous, as indicated by L3 cache miss rates observed on AMD EPYC processors. Our results suggest that future HPC architectures with larger caches and higher memory bandwidth would benefit the CFD community.
{"title":"Understanding superlinear speedup in current HPC architectures","authors":"Flavio Cesar Cunha Galeazzo, R. Gregor Weiß, Sergey Lesnik, Henrik Rusche, Andreas Ruopp","doi":"10.1088/1757-899x/1312/1/012009","DOIUrl":"https://doi.org/10.1088/1757-899x/1312/1/012009","url":null,"abstract":"The performance of OpenFOAM in strong scaling tests on HPC systems with AMD EPYC processors exhibits a pronounced superlinear speedup. Simple test cases show superlinear speedups of over 300%, which significantly impacts the efficient use of computing resources.With the last generation of HPC architectures, a superlinear speedup of about 10% to 20% was well expected and accepted by CFD users [1]. The measured superlinear speedup is much more pronounced and withstands the communication overhead to even larger scales.A detailed performance analysis of OpenFOAM follows, employing various High-Performance Computing (HPC) architectures, including AMD, ARM and Intel systems. The performance metric FVOPS (Finite VOlumes solved Per Second) is introduced to compare the performance of Computational Fluid Dynamics (CFD) applications when varying the grid size, as occurs in a strong scaling test. The achievable FVOPS depends on various factors, including the simulation type, boundary conditions, and especially the grid size of a use case. Analysing FVOPS on a single node level with varying grid size shows a significant difference in performance and cache utilization, which explains the large superlinear speedups seen in the strong scaling tests.Furthermore, FVOPS can be used as a simple benchmark to determine the optimal number of grid elements per rank to simulate a given use case at peak efficiency on a given platform, resulting in time, energy, and cost savings.The FVOPS metric also facilitates the direct comparison between different HPC architectures. The tests using AMD, ARM, and Intel processors show a peak in performance when employing around 10,000 grid elements per core. The presence of a large L3 cache on AMD processors is particularly advantageous, as indicated by L3 cache miss rates observed on AMD EPYC processors. Our results suggest that future HPC architectures with larger caches and higher memory bandwidth would benefit the CFD community.","PeriodicalId":14483,"journal":{"name":"IOP Conference Series: Materials Science and Engineering","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187340","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}
Pub Date : 2024-08-01DOI: 10.1088/1757-899x/1310/1/012003
F Adjei-Kyeremeh, C K Akuata, N Bansal, S Zischke, I Raffeis, A B Polaczek
The high strength and lightweight benefits of Al-Cu-Li alloys make them attractive for aerospace applications. The major strength contributing phase is the T1(Al2CuLi) phase. Although extensive reporting is known on its nucleation behaviour and structure in conventional T1 microstructures, little is known for additive manufacturing (AM). This work focusses on the comparative characterisation of T1 phase (structure, nucleation behaviour) in conventional (2099-T83), Powder Bed Fusion (PBF-LB/M) and Direct Energy Deposition (DED-LB/M) AA2099 microstructures. It is shown that with different AM processes and heat treatments, different T1 microstructures are achievable.
{"title":"Characterisation of T1 (Al2CuLi) Precipitates in Conventional (2099-T83) and Laser Additive Manufactured (PBF-LB/M, DED-LB/M) Microstructures","authors":"F Adjei-Kyeremeh, C K Akuata, N Bansal, S Zischke, I Raffeis, A B Polaczek","doi":"10.1088/1757-899x/1310/1/012003","DOIUrl":"https://doi.org/10.1088/1757-899x/1310/1/012003","url":null,"abstract":"The high strength and lightweight benefits of Al-Cu-Li alloys make them attractive for aerospace applications. The major strength contributing phase is the T<sub>1</sub>(Al<sub>2</sub>CuLi) phase. Although extensive reporting is known on its nucleation behaviour and structure in conventional T<sub>1</sub> microstructures, little is known for additive manufacturing (AM). This work focusses on the comparative characterisation of T<sub>1</sub> phase (structure, nucleation behaviour) in conventional (2099-T83), Powder Bed Fusion (PBF-LB/M) and Direct Energy Deposition (DED-LB/M) AA2099 microstructures. It is shown that with different AM processes and heat treatments, different T<sub>1</sub> microstructures are achievable.","PeriodicalId":14483,"journal":{"name":"IOP Conference Series: Materials Science and Engineering","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187468","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}
Pub Date : 2024-08-01DOI: 10.1088/1757-899x/1310/1/012018
A Sorea, P Valler, P Kjeldsteen, P Hjelmeborn
Metal binder jetting (MBJ) of AISI 904L super austenitic stainless steel makes it possible to produce complex components with a higher corrosion resistance compared to austenitic stainless steels such as AISI 304L and AISI 316L. The initial sintering trials resulted in a porous part with low corrosion resistance. As AISI 904L is a steel with austenitic phase throughout the entire sintering window, densification during sintering was inhibited which resulted in the reduced corrosion resistance due to open porosities. The trials were made with AISI 904L powder suited for MBJ but shaped through metal powder extrusion due to lack of printer availability. This paper will show how to enhance densification and utilize pickling in order to improve the corrosion resistance closer to the expected level comparable to cast and rolled material but with the shaping possibilities of MBJ.
{"title":"Improved corrosion resistance of powder manufactured AISI 904L parts by hot isostatic pressing post treatment","authors":"A Sorea, P Valler, P Kjeldsteen, P Hjelmeborn","doi":"10.1088/1757-899x/1310/1/012018","DOIUrl":"https://doi.org/10.1088/1757-899x/1310/1/012018","url":null,"abstract":"Metal binder jetting (MBJ) of AISI 904L super austenitic stainless steel makes it possible to produce complex components with a higher corrosion resistance compared to austenitic stainless steels such as AISI 304L and AISI 316L. The initial sintering trials resulted in a porous part with low corrosion resistance. As AISI 904L is a steel with austenitic phase throughout the entire sintering window, densification during sintering was inhibited which resulted in the reduced corrosion resistance due to open porosities. The trials were made with AISI 904L powder suited for MBJ but shaped through metal powder extrusion due to lack of printer availability. This paper will show how to enhance densification and utilize pickling in order to improve the corrosion resistance closer to the expected level comparable to cast and rolled material but with the shaping possibilities of MBJ.","PeriodicalId":14483,"journal":{"name":"IOP Conference Series: Materials Science and Engineering","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187458","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}
Pub Date : 2024-08-01DOI: 10.1088/1757-899x/1312/1/012003
M Politano, A Cupp, D Smith, A Schemmel, P R Jackson, J Zuercher
The Chicago Area Waterway System (CAWS) is a potential route for the migration of aquatic invasive species from the Mississippi River basin into the Great Lakes. Electric deterrence barriers were constructed in the Chicago Sanitary Ship Canal (CSSC), within CAWS, to prevent invasive fish from reaching the Great Lakes. Despite the high efficiency of these barriers, occasional maintenance events are a weakness in the system that fish can exploit to access the Great Lakes. This study aimed to assess the feasibility of a carbon dioxide (CO2) infusion system to deter fish during the maintenance of the electric barriers. A simplified two-fluid model was implemented in the OpenFOAM solver to represent the underwater CO2 bubble plume and predict the concentration of dissolved CO2 in the canal. Simulations under three canal flowrates and two sparger systems were conducted assuming a constant gas flowrate. Numerical results indicate that, for all simulated conditions, the CO2 concentration is not fully mixed creating passageways that invasive fish could potentially use to migrate upstream. Injecting 4-mm bubbles induces two large-scale recirculations that are expected to synergistically improve fish avoidance. On the other hand, injection of 20 μm bubbles results on almost immediate dissolution with minimal impact on the flow pattern. To improve effectiveness, a pulse system was proposed to create a CO2 gradient, and thus promote a more responsive behaviour from fish. According to the simulations, this system not only increases efficiency but also extends the operation of the CO2 barrier. Moreover, the pulse concept mitigates potential impact of elevated CO2 downstream of the CSSC.
{"title":"Evaluation of a carbon dioxide fish barrier with OpenFOAM","authors":"M Politano, A Cupp, D Smith, A Schemmel, P R Jackson, J Zuercher","doi":"10.1088/1757-899x/1312/1/012003","DOIUrl":"https://doi.org/10.1088/1757-899x/1312/1/012003","url":null,"abstract":"The Chicago Area Waterway System (CAWS) is a potential route for the migration of aquatic invasive species from the Mississippi River basin into the Great Lakes. Electric deterrence barriers were constructed in the Chicago Sanitary Ship Canal (CSSC), within CAWS, to prevent invasive fish from reaching the Great Lakes. Despite the high efficiency of these barriers, occasional maintenance events are a weakness in the system that fish can exploit to access the Great Lakes. This study aimed to assess the feasibility of a carbon dioxide (CO<sub>2</sub>) infusion system to deter fish during the maintenance of the electric barriers. A simplified two-fluid model was implemented in the OpenFOAM solver to represent the underwater CO<sub>2</sub> bubble plume and predict the concentration of dissolved CO<sub>2</sub> in the canal. Simulations under three canal flowrates and two sparger systems were conducted assuming a constant gas flowrate. Numerical results indicate that, for all simulated conditions, the CO<sub>2</sub> concentration is not fully mixed creating passageways that invasive fish could potentially use to migrate upstream. Injecting 4-mm bubbles induces two large-scale recirculations that are expected to synergistically improve fish avoidance. On the other hand, injection of 20 μm bubbles results on almost immediate dissolution with minimal impact on the flow pattern. To improve effectiveness, a pulse system was proposed to create a CO<sub>2</sub> gradient, and thus promote a more responsive behaviour from fish. According to the simulations, this system not only increases efficiency but also extends the operation of the CO<sub>2</sub> barrier. Moreover, the pulse concept mitigates potential impact of elevated CO<sub>2</sub> downstream of the CSSC.","PeriodicalId":14483,"journal":{"name":"IOP Conference Series: Materials Science and Engineering","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187309","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}
Pub Date : 2024-08-01DOI: 10.1088/1757-899x/1312/1/012012
Giulia Innocenti, Eric Segalerba, Joel Guerrero
The development of winglets has been motivated by the need to reduce lift-induced drag in aircraft. One of the main limitations, since they are fixed devices, is related to their inability in adapting to variable flight conditions. To address this issue, this study proposes the use of variable cant angle winglets that can be adjusted to optimize drag reduction under different flight conditions. In this study, we use the CFD solver OpenFOAM to investigate the effects of varying the winglet cant angle. Instead of a fully mesh morphing approach, a quasi-steady approach was taken where different winglet configurations were investigated by changing the cant angle from 0º to 70º. The main reason for taking this approach was to reduce the burden related to the dynamic meshing approach. The results obtained in this flight condition show an optimal cant angle, with respect to the aerodynamic efficiency, around 40º.
{"title":"Computational Fluid Dynamics Study on the Influence of Variable Cant Angle Winglets on Total Drag Reduction","authors":"Giulia Innocenti, Eric Segalerba, Joel Guerrero","doi":"10.1088/1757-899x/1312/1/012012","DOIUrl":"https://doi.org/10.1088/1757-899x/1312/1/012012","url":null,"abstract":"The development of winglets has been motivated by the need to reduce lift-induced drag in aircraft. One of the main limitations, since they are fixed devices, is related to their inability in adapting to variable flight conditions. To address this issue, this study proposes the use of variable cant angle winglets that can be adjusted to optimize drag reduction under different flight conditions. In this study, we use the CFD solver OpenFOAM to investigate the effects of varying the winglet cant angle. Instead of a fully mesh morphing approach, a quasi-steady approach was taken where different winglet configurations were investigated by changing the cant angle from 0º to 70º. The main reason for taking this approach was to reduce the burden related to the dynamic meshing approach. The results obtained in this flight condition show an optimal cant angle, with respect to the aerodynamic efficiency, around 40º.","PeriodicalId":14483,"journal":{"name":"IOP Conference Series: Materials Science and Engineering","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187312","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}
Pub Date : 2024-08-01DOI: 10.1088/1757-899x/1310/1/012028
J del Gaudio, J Donoghue, P J Withers, A Garner, K Mingard, M Gee, A Gholinia
Grain microstructures are important for a whole range of materials properties. With the widespread use of additive manufacturing (AM), current standards for grain boundary evaluation, such as ASTM E2627-13, may not be fit for purpose due to their microstructural complexity. They are notoriously anisotropic across a range of length scales due to the non-equilibrium nature of the solidification process and the tracking of the heat source. In this work we examine the grain microstructure of a nickel superalloy produced by laser powder bed AM by electron back scatter diffraction. We find that the guidelines provided by the ASTM E2627-13 are not suitable for such heterogeneous and anisotropic materials and some modified guidelines are provided on the field of view and EBSD step size that should be used to characterise such materials.
{"title":"Grain size assessment using EBSD on heterogeneous additively manufactured microstructures","authors":"J del Gaudio, J Donoghue, P J Withers, A Garner, K Mingard, M Gee, A Gholinia","doi":"10.1088/1757-899x/1310/1/012028","DOIUrl":"https://doi.org/10.1088/1757-899x/1310/1/012028","url":null,"abstract":"Grain microstructures are important for a whole range of materials properties. With the widespread use of additive manufacturing (AM), current standards for grain boundary evaluation, such as ASTM E2627-13, may not be fit for purpose due to their microstructural complexity. They are notoriously anisotropic across a range of length scales due to the non-equilibrium nature of the solidification process and the tracking of the heat source. In this work we examine the grain microstructure of a nickel superalloy produced by laser powder bed AM by electron back scatter diffraction. We find that the guidelines provided by the ASTM E2627-13 are not suitable for such heterogeneous and anisotropic materials and some modified guidelines are provided on the field of view and EBSD step size that should be used to characterise such materials.","PeriodicalId":14483,"journal":{"name":"IOP Conference Series: Materials Science and Engineering","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187409","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}
Pub Date : 2024-08-01DOI: 10.1088/1757-899x/1310/1/012037
Z Pan, Y Zhang, M Defer, X Xiao, D Juul Jensen, V K Nadimpalli
The microstructure of a stainless tool steel AISI 440C fabricated by laser powder bed fusion (L-PBF) without pre-heating of the build plate was characterized by multi-scale experimental methods. In combination with thermodynamic calculations, the solidification and cooling-down procedures were analyzed with the intention to understand the cracking behavior of high carbon tool steels processed by L-PBF. The results showed a fully austenitic structure in the as-built sample with sub-micro cellular structures and nano-sized carbides decorating the cell walls. Significant segregation exists merely at the intersection of cell walls while it is absent along high angle grain boundaries. Factors contributing to crack-free AISI 440C are discussed, providing guidelines for future L-PBF fabrication of high-carbon tool steels.
{"title":"Microstructural characterization of AISI 440C stainless tool steel fabricated by laser powder bed fusion","authors":"Z Pan, Y Zhang, M Defer, X Xiao, D Juul Jensen, V K Nadimpalli","doi":"10.1088/1757-899x/1310/1/012037","DOIUrl":"https://doi.org/10.1088/1757-899x/1310/1/012037","url":null,"abstract":"The microstructure of a stainless tool steel AISI 440C fabricated by laser powder bed fusion (L-PBF) without pre-heating of the build plate was characterized by multi-scale experimental methods. In combination with thermodynamic calculations, the solidification and cooling-down procedures were analyzed with the intention to understand the cracking behavior of high carbon tool steels processed by L-PBF. The results showed a fully austenitic structure in the as-built sample with sub-micro cellular structures and nano-sized carbides decorating the cell walls. Significant segregation exists merely at the intersection of cell walls while it is absent along high angle grain boundaries. Factors contributing to crack-free AISI 440C are discussed, providing guidelines for future L-PBF fabrication of high-carbon tool steels.","PeriodicalId":14483,"journal":{"name":"IOP Conference Series: Materials Science and Engineering","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187410","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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