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Powder based metal additive manufacturing processes like Powder Bed Fusion – Laser Beam utilize gasatomized metal powders as feedstock material. Typically, for nickel-based alloys such as Alloy 625, argongas is used during the atomization process. Considering the larger environmental impact of argon gascompared to nitrogen gas, and the increasing use of gas atomized metal powders, the environmentalimpact of powder based additive manufacturing techniques could be mitigated if gas atomization ofalloys such as Alloy 625 using nitrogen was possible. This work investigates the feasibility of tailoringan alloy to allow atomization using nitrogen gas while remaining within the Alloy 625 specification.This is achieved by limiting the nitrogen pick-up during the atomization process, primarily by reducingthe titanium content. The metallurgical implications of this tailored alloy and the subsequent atomizationusing nitrogen, as well as the attained microstructure from the Powder Bed Fusion – Laser Beam processis investigated and compared to a more common 625 alloy composition which was atomized usingargon. Furthermore, the microstructural development of the alloys after heat treatments are evaluated.Lastly corrosive properties, as well as tensile and impact properties are evaluated both in the as-builtand hot isostatic pressed condition.

Powder based metal additive manufacturing processes like Powder Bed Fusion – Laser Beam utilize gasatomized metal powders as feedstock material. Typically, for nickel-based alloys such as Alloy 625, argongas is used during the atomization process. Considering the larger environmental impact of argon gascompared to nitrogen gas, and the increasing use of gas atomized metal powders, the environmentalimpact of powder based additive manufacturing techniques could be mitigated if gas atomization ofalloys such as Alloy 625 using nitrogen was possible. This work investigates the feasibility of tailoringan alloy to allow atomization using nitrogen gas while remaining within the Alloy 625 specification.This is achieved by limiting the nitrogen pick-up during the atomization process, primarily by reducingthe titanium content. The metallurgical implications of this tailored alloy and the subsequent atomizationusing nitrogen, as well as the attained microstructure from the Powder Bed Fusion – Laser Beam processis investigated and compared to a more common 625 alloy composition which was atomized usingargon. Furthermore, the microstructural development of the alloys after heat treatments are evaluated.Lastly corrosive properties, as well as tensile and impact properties are evaluated both in the as-builtand hot isostatic pressed condition.

Powder based metal additive manufacturing processes like Powder Bed Fusion – Laser Beam utilize gasatomized metal powders as feedstock material. Typically, for nickel-based alloys such as Alloy 625, argongas is used during the atomization process. Considering the larger environmental impact of argon gascompared to nitrogen gas, and the increasing use of gas atomized metal powders, the environmentalimpact of powder based additive manufacturing techniques could be mitigated if gas atomization ofalloys such as Alloy 625 using nitrogen was possible. This work investigates the feasibility of tailoringan alloy to allow atomization using nitrogen gas while remaining within the Alloy 625 specification.This is achieved by limiting the nitrogen pick-up during the atomization process, primarily by reducingthe titanium content. The metallurgical implications of this tailored alloy and the subsequent atomizationusing nitrogen, as well as the attained microstructure from the Powder Bed Fusion – Laser Beam processis investigated and compared to a more common 625 alloy composition which was atomized usingargon. Furthermore, the microstructural development of the alloys after heat treatments are evaluated.Lastly corrosive properties, as well as tensile and impact properties are evaluated both in the as-builtand hot isostatic pressed condition.

Powder based metal additive manufacturing processes like Powder Bed Fusion – Laser Beam utilize gasatomized metal powders as feedstock material. Typically, for nickel-based alloys such as Alloy 625, argongas is used during the atomization process. Considering the larger environmental impact of argon gascompared to nitrogen gas, and the increasing use of gas atomized metal powders, the environmentalimpact of powder based additive manufacturing techniques could be mitigated if gas atomization ofalloys such as Alloy 625 using nitrogen was possible. This work investigates the feasibility of tailoringan alloy to allow atomization using nitrogen gas while remaining within the Alloy 625 specification.This is achieved by limiting the nitrogen pick-up during the atomization process, primarily by reducingthe titanium content. The metallurgical implications of this tailored alloy and the subsequent atomizationusing nitrogen, as well as the attained microstructure from the Powder Bed Fusion – Laser Beam processis investigated and compared to a more common 625 alloy composition which was atomized usingargon. Furthermore, the microstructural development of the alloys after heat treatments are evaluated.Lastly corrosive properties, as well as tensile and impact properties are evaluated both in the as-builtand hot isostatic pressed condition.

The microstructure response of laser-powder bed fusion (L-PBF)-processed ferritic stainless steel (AISI 441) during post-heat treatments is studied in detail. Focus is on the precipitation kinetics of the Nb-rich phases: Laves (Fe2Nb) and the cubic carbo-nitride (NbC), as well as the grain structure evolution. The evolution of the precipitates is characterized using scanning and transmission electron microscopy (SEM and TEM) and the experimental results are used to calibrate precipitation kinetics simulations using the precipitation module (TC-PRISMA) within the Thermo-Calc Software package. The calculations reproduce the main trend for both the mean radii for the Laves phase and the NbC, and the amount of Laves phase, as a function of temperature. The calibrated model can be used to optimize the post-heat treatment of additively manufactured ferritic stainless steel components and offer a creator tool for process and structure linkages in an integrated computational materials engineering (ICME) framework for alloy and process development of additively manufactured ferritic steels., QC 20230308

Powder based metal additive manufacturing processes like Powder Bed Fusion – Laser Beam utilize gasatomized metal powders as feedstock material. Typically, for nickel-based alloys such as Alloy 625, argongas is used during the atomization process. Considering the larger environmental impact of argon gascompared to nitrogen gas, and the increasing use of gas atomized metal powders, the environmentalimpact of powder based additive manufacturing techniques could be mitigated if gas atomization ofalloys such as Alloy 625 using nitrogen was possible. This work investigates the feasibility of tailoringan alloy to allow atomization using nitrogen gas while remaining within the Alloy 625 specification.This is achieved by limiting the nitrogen pick-up during the atomization process, primarily by reducingthe titanium content. The metallurgical implications of this tailored alloy and the subsequent atomizationusing nitrogen, as well as the attained microstructure from the Powder Bed Fusion – Laser Beam processis investigated and compared to a more common 625 alloy composition which was atomized usingargon. Furthermore, the microstructural development of the alloys after heat treatments are evaluated.Lastly corrosive properties, as well as tensile and impact properties are evaluated both in the as-builtand hot isostatic pressed condition.

Impact toughness of Alloy 718 built via laser powder bed fusion (LPBF) in as-built and thermally post treated conditions were investigated. The effect of various stages in the thermal post-treatment, including stress relief, hot isostatic pressing, solution treatment, and aging on the microstructure, texture, ductility, hardness, and impact toughness were studied. The greatest impact toughness was found in the as-built Alloy 718 material, associated with the high ductility of the material. The ductility results were also inversely related to the hardness of the investigated materials. Where the material with the highest ductility had the lowest hardness etc. Anisotropy in the impact toughness behavior was present in the as-built and post-heat treated specimens, which was explained by the presence of texture in all of the investigated material. With the applied heat treatments, recrystallization occurred and the preferential crystal orientations were randomized, decreasing the texture. The thermal post-treating conditions rendered different types of microstructures, with various grain sizes. The carbide content remained the same for the three investigated thermal post-treating conditions., This project is a part of a larger project within the SUMAN-NEXT project (project number 20160281), which is finaced by the KK-foundation (Sweden), where several collaborators, such as Sandvik, GKN Aerospace Sweden AB, Quintus Technologies AB, Arcam-EBM, and Element are involved. The authors would therefore like to thank these project partners. The authors would also like to specifically thank Element (Karlskoga, Sweden) for performing the Charpy impact testing, Siemens Industrial Turbomachinery AB for specimen manufacturing, GKN Aerospace Sweden AB for performing the heat treatments, and Quintus for performing the HIP treatments. For his assistance, the authors would like to thank Dr. Esmaeil Sadeghi.

Impact toughness of Alloy 718 built via laser powder bed fusion (LPBF) in as-built and thermally post treated conditions were investigated. The effect of various stages in the thermal post-treatment, including stress relief, hot isostatic pressing, solution treatment, and aging on the microstructure, texture, ductility, hardness, and impact toughness were studied. The greatest impact toughness was found in the as-built Alloy 718 material, associated with the high ductility of the material. The ductility results were also inversely related to the hardness of the investigated materials. Where the material with the highest ductility had the lowest hardness etc. Anisotropy in the impact toughness behavior was present in the as-built and post-heat treated specimens, which was explained by the presence of texture in all of the investigated material. With the applied heat treatments, recrystallization occurred and the preferential crystal orientations were randomized, decreasing the texture. The thermal post-treating conditions rendered different types of microstructures, with various grain sizes. The carbide content remained the same for the three investigated thermal post-treating conditions., This project is a part of a larger project within the SUMAN-NEXT project (project number 20160281), which is finaced by the KK-foundation (Sweden), where several collaborators, such as Sandvik, GKN Aerospace Sweden AB, Quintus Technologies AB, Arcam-EBM, and Element are involved. The authors would therefore like to thank these project partners. The authors would also like to specifically thank Element (Karlskoga, Sweden) for performing the Charpy impact testing, Siemens Industrial Turbomachinery AB for specimen manufacturing, GKN Aerospace Sweden AB for performing the heat treatments, and Quintus for performing the HIP treatments. For his assistance, the authors would like to thank Dr. Esmaeil Sadeghi.

Impact toughness of Alloy 718 built via laser powder bed fusion (LPBF) in as-built and thermally post treated conditions were investigated. The effect of various stages in the thermal post-treatment, including stress relief, hot isostatic pressing, solution treatment, and aging on the microstructure, texture, ductility, hardness, and impact toughness were studied. The greatest impact toughness was found in the as-built Alloy 718 material, associated with the high ductility of the material. The ductility results were also inversely related to the hardness of the investigated materials. Where the material with the highest ductility had the lowest hardness etc. Anisotropy in the impact toughness behavior was present in the as-built and post-heat treated specimens, which was explained by the presence of texture in all of the investigated material. With the applied heat treatments, recrystallization occurred and the preferential crystal orientations were randomized, decreasing the texture. The thermal post-treating conditions rendered different types of microstructures, with various grain sizes. The carbide content remained the same for the three investigated thermal post-treating conditions., This project is a part of a larger project within the SUMAN-NEXT project (project number 20160281), which is finaced by the KK-foundation (Sweden), where several collaborators, such as Sandvik, GKN Aerospace Sweden AB, Quintus Technologies AB, Arcam-EBM, and Element are involved. The authors would therefore like to thank these project partners. The authors would also like to specifically thank Element (Karlskoga, Sweden) for performing the Charpy impact testing, Siemens Industrial Turbomachinery AB for specimen manufacturing, GKN Aerospace Sweden AB for performing the heat treatments, and Quintus for performing the HIP treatments. For his assistance, the authors would like to thank Dr. Esmaeil Sadeghi.

Impact toughness of Alloy 718 built via laser powder bed fusion (LPBF) in as-built and thermally post treated conditions were investigated. The effect of various stages in the thermal post-treatment, including stress relief, hot isostatic pressing, solution treatment, and aging on the microstructure, texture, ductility, hardness, and impact toughness were studied. The greatest impact toughness was found in the as-built Alloy 718 material, associated with the high ductility of the material. The ductility results were also inversely related to the hardness of the investigated materials. Where the material with the highest ductility had the lowest hardness etc. Anisotropy in the impact toughness behavior was present in the as-built and post-heat treated specimens, which was explained by the presence of texture in all of the investigated material. With the applied heat treatments, recrystallization occurred and the preferential crystal orientations were randomized, decreasing the texture. The thermal post-treating conditions rendered different types of microstructures, with various grain sizes. The carbide content remained the same for the three investigated thermal post-treating conditions., This project is a part of a larger project within the SUMAN-NEXT project (project number 20160281), which is finaced by the KK-foundation (Sweden), where several collaborators, such as Sandvik, GKN Aerospace Sweden AB, Quintus Technologies AB, Arcam-EBM, and Element are involved. The authors would therefore like to thank these project partners. The authors would also like to specifically thank Element (Karlskoga, Sweden) for performing the Charpy impact testing, Siemens Industrial Turbomachinery AB for specimen manufacturing, GKN Aerospace Sweden AB for performing the heat treatments, and Quintus for performing the HIP treatments. For his assistance, the authors would like to thank Dr. Esmaeil Sadeghi.

Impact toughness of Alloy 718 built via laser powder bed fusion (LPBF) in as-built and thermally post treated conditions were investigated. The effect of various stages in the thermal post-treatment, including stress relief, hot isostatic pressing, solution treatment, and aging on the microstructure, texture, ductility, hardness, and impact toughness were studied. The greatest impact toughness was found in the as-built Alloy 718 material, associated with the high ductility of the material. The ductility results were also inversely related to the hardness of the investigated materials. Where the material with the highest ductility had the lowest hardness etc. Anisotropy in the impact toughness behavior was present in the as-built and post-heat treated specimens, which was explained by the presence of texture in all of the investigated material. With the applied heat treatments, recrystallization occurred and the preferential crystal orientations were randomized, decreasing the texture. The thermal post-treating conditions rendered different types of microstructures, with various grain sizes. The carbide content remained the same for the three investigated thermal post-treating conditions., This project is a part of a larger project within the SUMAN-NEXT project (project number 20160281), which is finaced by the KK-foundation (Sweden), where several collaborators, such as Sandvik, GKN Aerospace Sweden AB, Quintus Technologies AB, Arcam-EBM, and Element are involved. The authors would therefore like to thank these project partners. The authors would also like to specifically thank Element (Karlskoga, Sweden) for performing the Charpy impact testing, Siemens Industrial Turbomachinery AB for specimen manufacturing, GKN Aerospace Sweden AB for performing the heat treatments, and Quintus for performing the HIP treatments. For his assistance, the authors would like to thank Dr. Esmaeil Sadeghi.

Impact toughness of Alloy 718 built via laser powder bed fusion (LPBF) in as-built and thermally post treated conditions were investigated. The effect of various stages in the thermal post-treatment, including stress relief, hot isostatic pressing, solution treatment, and aging on the microstructure, texture, ductility, hardness, and impact toughness were studied. The greatest impact toughness was found in the as-built Alloy 718 material, associated with the high ductility of the material. The ductility results were also inversely related to the hardness of the investigated materials. Where the material with the highest ductility had the lowest hardness etc. Anisotropy in the impact toughness behavior was present in the as-built and post-heat treated specimens, which was explained by the presence of texture in all of the investigated material. With the applied heat treatments, recrystallization occurred and the preferential crystal orientations were randomized, decreasing the texture. The thermal post-treating conditions rendered different types of microstructures, with various grain sizes. The carbide content remained the same for the three investigated thermal post-treating conditions., This project is a part of a larger project within the SUMAN-NEXT project (project number 20160281), which is finaced by the KK-foundation (Sweden), where several collaborators, such as Sandvik, GKN Aerospace Sweden AB, Quintus Technologies AB, Arcam-EBM, and Element are involved. The authors would therefore like to thank these project partners. The authors would also like to specifically thank Element (Karlskoga, Sweden) for performing the Charpy impact testing, Siemens Industrial Turbomachinery AB for specimen manufacturing, GKN Aerospace Sweden AB for performing the heat treatments, and Quintus for performing the HIP treatments. For his assistance, the authors would like to thank Dr. Esmaeil Sadeghi.

Electron beam-powder bed fusion (EB-PBF), a high-temperature additive manufacturing (AM) technique, shows great promise in the production of high-quality metallic parts in different applications such as the aerospace industry. To achieve a higher build efficiency, it is ideal to build multiple parts together with as low spacing as possible between the respective parts. In the EB-PBF technique, there are many unknown variations in microstructural characteristics and functional performance that could be induced as a result of the location of the parts on the build plate, gaps between the parts and part geometry, etc. In the present study, the variations in the microstructure and corrosion performance as a function of the parts location on the build plate in the EB-PBF process were investigated. The microstructural features were correlated with the thermal history of the samples built in different locations on the build plate, including exterior (the outermost), middle (between the outermost and innermost), and interior (the innermost) regions. The cubic coupons located in the exterior regions showed increased level (~ 20 %) of defects (mainly in the form of shrinkage pores) and lower level (~ 30-35 %) of Nb-rich phase fraction due to their higher cooling rates compared to the interior and middle samples. Electrochemical investigations showed that the location indirectly had a substantial influence on the corrosion behavior, verified by a significant increase in polarization resistance (Rp) from the exterior (2.1 ± 0.3 kΩ.cm2) to interior regions (39.2 ± 4.1 kΩ.cm2). © 2020, The Author(s).

Electron beam-powder bed fusion (EB-PBF), a high-temperature additive manufacturing (AM) technique, shows great promise in the production of high-quality metallic parts in different applications such as the aerospace industry. To achieve a higher build efficiency, it is ideal to build multiple parts together with as low spacing as possible between the respective parts. In the EB-PBF technique, there are many unknown variations in microstructural characteristics and functional performance that could be induced as a result of the location of the parts on the build plate, gaps between the parts and part geometry, etc. In the present study, the variations in the microstructure and corrosion performance as a function of the parts location on the build plate in the EB-PBF process were investigated. The microstructural features were correlated with the thermal history of the samples built in different locations on the build plate, including exterior (the outermost), middle (between the outermost and innermost), and interior (the innermost) regions. The cubic coupons located in the exterior regions showed increased level (~ 20 %) of defects (mainly in the form of shrinkage pores) and lower level (~ 30-35 %) of Nb-rich phase fraction due to their higher cooling rates compared to the interior and middle samples. Electrochemical investigations showed that the location indirectly had a substantial influence on the corrosion behavior, verified by a significant increase in polarization resistance (Rp) from the exterior (2.1 ± 0.3 kΩ.cm2) to interior regions (39.2 ± 4.1 kΩ.cm2). © 2020, The Author(s).

Electron beam-powder bed fusion (EB-PBF), a high-temperature additive manufacturing (AM) technique, shows great promise in the production of high-quality metallic parts in different applications such as the aerospace industry. To achieve a higher build efficiency, it is ideal to build multiple parts together with as low spacing as possible between the respective parts. In the EB-PBF technique, there are many unknown variations in microstructural characteristics and functional performance that could be induced as a result of the location of the parts on the build plate, gaps between the parts and part geometry, etc. In the present study, the variations in the microstructure and corrosion performance as a function of the parts location on the build plate in the EB-PBF process were investigated. The microstructural features were correlated with the thermal history of the samples built in different locations on the build plate, including exterior (the outermost), middle (between the outermost and innermost), and interior (the innermost) regions. The cubic coupons located in the exterior regions showed increased level (~ 20 %) of defects (mainly in the form of shrinkage pores) and lower level (~ 30-35 %) of Nb-rich phase fraction due to their higher cooling rates compared to the interior and middle samples. Electrochemical investigations showed that the location indirectly had a substantial influence on the corrosion behavior, verified by a significant increase in polarization resistance (Rp) from the exterior (2.1 ± 0.3 kΩ.cm2) to interior regions (39.2 ± 4.1 kΩ.cm2). © 2020, The Author(s).

Electron beam-powder bed fusion (EB-PBF), a high-temperature additive manufacturing (AM) technique, shows great promise in the production of high-quality metallic parts in different applications such as the aerospace industry. To achieve a higher build efficiency, it is ideal to build multiple parts together with as low spacing as possible between the respective parts. In the EB-PBF technique, there are many unknown variations in microstructural characteristics and functional performance that could be induced as a result of the location of the parts on the build plate, gaps between the parts and part geometry, etc. In the present study, the variations in the microstructure and corrosion performance as a function of the parts location on the build plate in the EB-PBF process were investigated. The microstructural features were correlated with the thermal history of the samples built in different locations on the build plate, including exterior (the outermost), middle (between the outermost and innermost), and interior (the innermost) regions. The cubic coupons located in the exterior regions showed increased level (~ 20 %) of defects (mainly in the form of shrinkage pores) and lower level (~ 30-35 %) of Nb-rich phase fraction due to their higher cooling rates compared to the interior and middle samples. Electrochemical investigations showed that the location indirectly had a substantial influence on the corrosion behavior, verified by a significant increase in polarization resistance (Rp) from the exterior (2.1 ± 0.3 kΩ.cm2) to interior regions (39.2 ± 4.1 kΩ.cm2). © 2020, The Author(s).

Electron beam-powder bed fusion (EB-PBF), a high-temperature additive manufacturing (AM) technique, shows great promise in the production of high-quality metallic parts in different applications such as the aerospace industry. To achieve a higher build efficiency, it is ideal to build multiple parts together with as low spacing as possible between the respective parts. In the EB-PBF technique, there are many unknown variations in microstructural characteristics and functional performance that could be induced as a result of the location of the parts on the build plate, gaps between the parts and part geometry, etc. In the present study, the variations in the microstructure and corrosion performance as a function of the parts location on the build plate in the EB-PBF process were investigated. The microstructural features were correlated with the thermal history of the samples built in different locations on the build plate, including exterior (the outermost), middle (between the outermost and innermost), and interior (the innermost) regions. The cubic coupons located in the exterior regions showed increased level (~ 20 %) of defects (mainly in the form of shrinkage pores) and lower level (~ 30-35 %) of Nb-rich phase fraction due to their higher cooling rates compared to the interior and middle samples. Electrochemical investigations showed that the location indirectly had a substantial influence on the corrosion behavior, verified by a significant increase in polarization resistance (Rp) from the exterior (2.1 ± 0.3 kΩ.cm2) to interior regions (39.2 ± 4.1 kΩ.cm2). © 2020, The Author(s).

Additive manufacturing is steadily gaining acceptance in certain industry segments as a process for the manufacturing of dense metallic components. The Ni-based superalloys belonging to the Inconel family have for many years been in focus for AM research and AM produced components are now becoming commercially available. However, it is still unclear how the microstructural anisotropy, inherent to most AM materials, affects the material performance in a given application. The anisotropy may e.g. influence the mechanical properties and the performance in certain tribological situations, such as when subjected to rolling contact fatigue. Like most AM methods, the powder bed fusion - laser beam process gives the produced components a relatively rough surface. To perform well in demanding tribological situations, the components are commonly machined to a smooth finish. In this work, Inconel 625 produced using PBF-LB is evaluated in a rolling contact fatigue test. Test cylinders (empty set 10 mm) have been produced using different build directions and scan strategies, resulting in varying microstructures and textures. In the rolling contact fatigue test, a cylindrical sample is mounted between two empty set 140 mm metal rollers, pulled together via a spring. After testing, the contact tracks are studied using SEM and EBSD to reveal cracks. Cracks were analysed with respect to the microstructure and anisotropies. It was found that the anisotropy influences both the nucleation and growth of cracks. The AM produced specimens were also found to be more prone to transgranular cracking than conventional Inconel 625, which predominantly displayed intergranular cracks.

Additive manufacturing is steadily gaining acceptance in certain industry segments as a process for the manufacturing of dense metallic components. The Ni-based superalloys belonging to the Inconel family have for many years been in focus for AM research and AM produced components are now becoming commercially available. However, it is still unclear how the microstructural anisotropy, inherent to most AM materials, affects the material performance in a given application. The anisotropy may e.g. influence the mechanical properties and the performance in certain tribological situations, such as when subjected to rolling contact fatigue. Like most AM methods, the powder bed fusion - laser beam process gives the produced components a relatively rough surface. To perform well in demanding tribological situations, the components are commonly machined to a smooth finish. In this work, Inconel 625 produced using PBF-LB is evaluated in a rolling contact fatigue test. Test cylinders (empty set 10 mm) have been produced using different build directions and scan strategies, resulting in varying microstructures and textures. In the rolling contact fatigue test, a cylindrical sample is mounted between two empty set 140 mm metal rollers, pulled together via a spring. After testing, the contact tracks are studied using SEM and EBSD to reveal cracks. Cracks were analysed with respect to the microstructure and anisotropies. It was found that the anisotropy influences both the nucleation and growth of cracks. The AM produced specimens were also found to be more prone to transgranular cracking than conventional Inconel 625, which predominantly displayed intergranular cracks.

Additive manufacturing is steadily gaining acceptance in certain industry segments as a process for the manufacturing of dense metallic components. The Ni-based superalloys belonging to the Inconel family have for many years been in focus for AM research and AM produced components are now becoming commercially available. However, it is still unclear how the microstructural anisotropy, inherent to most AM materials, affects the material performance in a given application. The anisotropy may e.g. influence the mechanical properties and the performance in certain tribological situations, such as when subjected to rolling contact fatigue. Like most AM methods, the powder bed fusion - laser beam process gives the produced components a relatively rough surface. To perform well in demanding tribological situations, the components are commonly machined to a smooth finish. In this work, Inconel 625 produced using PBF-LB is evaluated in a rolling contact fatigue test. Test cylinders (empty set 10 mm) have been produced using different build directions and scan strategies, resulting in varying microstructures and textures. In the rolling contact fatigue test, a cylindrical sample is mounted between two empty set 140 mm metal rollers, pulled together via a spring. After testing, the contact tracks are studied using SEM and EBSD to reveal cracks. Cracks were analysed with respect to the microstructure and anisotropies. It was found that the anisotropy influences both the nucleation and growth of cracks. The AM produced specimens were also found to be more prone to transgranular cracking than conventional Inconel 625, which predominantly displayed intergranular cracks.

Additive manufacturing is steadily gaining acceptance in certain industry segments as a process for the manufacturing of dense metallic components. The Ni-based superalloys belonging to the Inconel family have for many years been in focus for AM research and AM produced components are now becoming commercially available. However, it is still unclear how the microstructural anisotropy, inherent to most AM materials, affects the material performance in a given application. The anisotropy may e.g. influence the mechanical properties and the performance in certain tribological situations, such as when subjected to rolling contact fatigue. Like most AM methods, the powder bed fusion - laser beam process gives the produced components a relatively rough surface. To perform well in demanding tribological situations, the components are commonly machined to a smooth finish. In this work, Inconel 625 produced using PBF-LB is evaluated in a rolling contact fatigue test. Test cylinders (empty set 10 mm) have been produced using different build directions and scan strategies, resulting in varying microstructures and textures. In the rolling contact fatigue test, a cylindrical sample is mounted between two empty set 140 mm metal rollers, pulled together via a spring. After testing, the contact tracks are studied using SEM and EBSD to reveal cracks. Cracks were analysed with respect to the microstructure and anisotropies. It was found that the anisotropy influences both the nucleation and growth of cracks. The AM produced specimens were also found to be more prone to transgranular cracking than conventional Inconel 625, which predominantly displayed intergranular cracks.

Additive manufacturing is steadily gaining acceptance in certain industry segments as a process for the manufacturing of dense metallic components. The Ni-based superalloys belonging to the Inconel family have for many years been in focus for AM research and AM produced components are now becoming commercially available. However, it is still unclear how the microstructural anisotropy, inherent to most AM materials, affects the material performance in a given application. The anisotropy may e.g. influence the mechanical properties and the performance in certain tribological situations, such as when subjected to rolling contact fatigue. Like most AM methods, the powder bed fusion - laser beam process gives the produced components a relatively rough surface. To perform well in demanding tribological situations, the components are commonly machined to a smooth finish. In this work, Inconel 625 produced using PBF-LB is evaluated in a rolling contact fatigue test. Test cylinders (empty set 10 mm) have been produced using different build directions and scan strategies, resulting in varying microstructures and textures. In the rolling contact fatigue test, a cylindrical sample is mounted between two empty set 140 mm metal rollers, pulled together via a spring. After testing, the contact tracks are studied using SEM and EBSD to reveal cracks. Cracks were analysed with respect to the microstructure and anisotropies. It was found that the anisotropy influences both the nucleation and growth of cracks. The AM produced specimens were also found to be more prone to transgranular cracking than conventional Inconel 625, which predominantly displayed intergranular cracks.