Pub Date : 2025-07-01Epub Date: 2025-07-22DOI: 10.1016/j.addlet.2025.100308
Amit Kumar Singh , Prithvi D. Awasthi , Ankita Roy , Priyanka Agrawal , Aishani Sharma , Anurag Gumaste , Ravi Sankar Haridas , Rajiv S. Mishra
Additive manufacturing has opened a paradigm for the efficient and quick production of lightweight lattice structures showing characteristic high specific strength (strength-to-weight ratios). The current study describes the development of methodology and utilization of high strength Al alloy for building complex lattice using additive manufacturing. Thin plate lattice <1 mm of Al-Ni-Ti-Zr-Mn alloy with wide processing window, achieving an average yield strength of 63.13±3.32 MPa in compression, with 28 % lower density than Ti-6Al-4V demonstrates a successful design of Al-Ni-Ti-Zr-Mn alloys using laser beam powder bed fusion (PBF-LB). The mitigation of cracks within thin plate parallel to the loading axis was achieved through the formation of Al-Al₃Ni eutectic channels, exploiting the rapid solidification of this short-freezing-range alloy. In addition to multi-topology structural design, the enhanced strength is attributed to hierarchical microstructure featuring L1₂ phases, bimodal grain distribution, and solid solution strengthening by Mn. This work establishes a printability-performance synergy of Al-Ni-Ti-Zr-Mn alloy for thin plate complex lattice, advancing the use of metamaterials through PBF-LB.
{"title":"Novel high specific-strength multi-topology Al-Ni-Ti-Zr-Mn alloy using laser powder bed fusion additive manufacturing","authors":"Amit Kumar Singh , Prithvi D. Awasthi , Ankita Roy , Priyanka Agrawal , Aishani Sharma , Anurag Gumaste , Ravi Sankar Haridas , Rajiv S. Mishra","doi":"10.1016/j.addlet.2025.100308","DOIUrl":"10.1016/j.addlet.2025.100308","url":null,"abstract":"<div><div>Additive manufacturing has opened a paradigm for the efficient and quick production of lightweight lattice structures showing characteristic high specific strength (strength-to-weight ratios). The current study describes the development of methodology and utilization of high strength Al alloy for building complex lattice using additive manufacturing. Thin plate lattice <1 mm of Al-Ni-Ti-Zr-Mn alloy with wide processing window, achieving an average yield strength of 63.13±3.32 MPa in compression, with 28 % lower density than Ti-6Al-4V demonstrates a successful design of Al-Ni-Ti-Zr-Mn alloys using laser beam powder bed fusion (PBF-LB). The mitigation of cracks within thin plate parallel to the loading axis was achieved through the formation of Al-Al₃Ni eutectic channels, exploiting the rapid solidification of this short-freezing-range alloy. In addition to multi-topology structural design, the enhanced strength is attributed to hierarchical microstructure featuring L1₂ phases, bimodal grain distribution, and solid solution strengthening by Mn. This work establishes a printability-performance synergy of Al-Ni-Ti-Zr-Mn alloy for thin plate complex lattice, advancing the use of metamaterials through PBF-LB.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"14 ","pages":"Article 100308"},"PeriodicalIF":4.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686273","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}
The light-weighting of high-end equipment structural components is an eternal pursuit in structural engineering. The development of Laser Powder Bed Fusion (L-PBF) technology has enabled the easy fabrication of lattice structure materials, which exhibit exceptional mechanical properties. The present study investigates the mechanical properties and deformation processes of ten Ti6Al4V lattice structures (Primitive, Diamond, Fischer-Koch, I-WP, Gyroid; 6-Layered Plate, 4-Layered Plate, Truss Plate; Auxetic honeycomb X, and Auxetic honeycomb Y) under a transverse impact loading. Firstly, it was found that the truss plate and 4-layered plate exhibited the highest specific absorbed energy (SAE) of 38.67 J/(g∙cm-3) and specific peak force (SPF) of 6033 N/(g∙cm-3), respectively. The Negative Poisson's ratio structure demonstrated the best damage tolerance during the impact test procedure. Meanwhile, the TPMS structures, which exhibit similar deformation behavior and shear failure modes, have closely matched peak force values. These findings provide critical guidance for aerospace and automotive applications requiring mass-efficient energy absorption.
{"title":"Damage modes and mechanical properties of Ti6Al4V lattice structures under transverse impact loading","authors":"Minghao Huang , Yixiao Luo , Tenglong Xie , Xin Yang , Shenghang Xu , Chen Chang , Chao Ding , Huiping Tang","doi":"10.1016/j.addlet.2025.100294","DOIUrl":"10.1016/j.addlet.2025.100294","url":null,"abstract":"<div><div>The light-weighting of high-end equipment structural components is an eternal pursuit in structural engineering. The development of Laser Powder Bed Fusion (L-PBF) technology has enabled the easy fabrication of lattice structure materials, which exhibit exceptional mechanical properties. The present study investigates the mechanical properties and deformation processes of ten Ti6Al4V lattice structures (Primitive, Diamond, Fischer-Koch, I-WP, Gyroid; 6-Layered Plate, 4-Layered Plate, Truss Plate; Auxetic honeycomb X, and Auxetic honeycomb Y) under a transverse impact loading. Firstly, it was found that the truss plate and 4-layered plate exhibited the highest specific absorbed energy (SAE) of 38.67 J/(g∙cm<sup>-3</sup>) and specific peak force (SPF) of 6033 N/(g∙cm<sup>-3</sup>), respectively. The Negative Poisson's ratio structure demonstrated the best damage tolerance during the impact test procedure. Meanwhile, the TPMS structures, which exhibit similar deformation behavior and shear failure modes, have closely matched peak force values. These findings provide critical guidance for aerospace and automotive applications requiring mass-efficient energy absorption.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"14 ","pages":"Article 100294"},"PeriodicalIF":4.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144194651","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 : 2025-07-01Epub Date: 2025-04-28DOI: 10.1016/j.addlet.2025.100284
Jonas Grünewald, Katrin Wudy
The research trend to investigate the influence of alternative beam profiles on the process and component properties in laser-based powder bed fusion raises the question of how to compare the processes and process results generated with various beam profiles in different sizes. The current state of research mainly examines the process simplified on a single-track basis or addresses isolated aspects, such as the change in beam profile and size with constant absolute process parameters, which neglects the cross-effects of these parameters. Therefore, this paper presents a new approach to consider varied process parameters and their cross effects. The approach is based on a simple heat conduction model and allows the creation of beam shape and size-independent process maps. These dimensionless process maps are created by replacing the common dimensioned process parameters (laser power and scan speed) with combined dimensionless parameters (dimensionless enthalpy and Peclét number, each extended by a dimensionless hatch distance). This way, the parameters consider material and beam properties. Within the process maps, the process boundaries are predicted by simple geometric conditions of the calculated melt pools using the introduced heat conduction model. The model is experimentally validated by conducting a comprehensive parameter study using a multidimensional design of experiments with seven different beam profiles in various sizes and varying laser power, scanning speed, and hatch distance processing AISI 316L. The relative density and surface roughness are evaluated in the experiments. The predicted and experimentally determined process limits are in excellent agreement.
{"title":"Dimensionless process windows in laser-based powder bed fusion of AISI 316L using ring-shaped beam profiles","authors":"Jonas Grünewald, Katrin Wudy","doi":"10.1016/j.addlet.2025.100284","DOIUrl":"10.1016/j.addlet.2025.100284","url":null,"abstract":"<div><div>The research trend to investigate the influence of alternative beam profiles on the process and component properties in laser-based powder bed fusion raises the question of how to compare the processes and process results generated with various beam profiles in different sizes. The current state of research mainly examines the process simplified on a single-track basis or addresses isolated aspects, such as the change in beam profile and size with constant absolute process parameters, which neglects the cross-effects of these parameters. Therefore, this paper presents a new approach to consider varied process parameters and their cross effects. The approach is based on a simple heat conduction model and allows the creation of beam shape and size-independent process maps. These dimensionless process maps are created by replacing the common dimensioned process parameters (laser power and scan speed) with combined dimensionless parameters (dimensionless enthalpy and Peclét number, each extended by a dimensionless hatch distance). This way, the parameters consider material and beam properties. Within the process maps, the process boundaries are predicted by simple geometric conditions of the calculated melt pools using the introduced heat conduction model. The model is experimentally validated by conducting a comprehensive parameter study using a multidimensional design of experiments with seven different beam profiles in various sizes and varying laser power, scanning speed, and hatch distance processing AISI 316L. The relative density and surface roughness are evaluated in the experiments. The predicted and experimentally determined process limits are in excellent agreement.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"14 ","pages":"Article 100284"},"PeriodicalIF":4.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143906639","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 : 2025-07-01Epub Date: 2025-05-08DOI: 10.1016/j.addlet.2025.100288
Sweta Baruah, Joshua Hoekstra, Tony Schmitz
With the growing emphasis on supply chain resilience and efficiency, manufacturers are increasingly exploring sustainable material reuse strategies. One promising approach is the upcycling of machining chips into usable feedstock for additive friction stir deposition (AFSD), a solid-state additive manufacturing process. AFSD has demonstrated potential for integrating into hybrid manufacturing workflows, offering advantages such as reduced material waste and enhanced process sustainability. However, for chip upcycling to produce AFSD feedstock to be viable, its production cost must be accurately assessed and compared to conventional feedstock options. Estimating these costs poses challenges due to the complexity of the upcycling process and its associated variables. This paper presents a cost modeling framework for the production of upcycled bars from machining chips, specifically as AFSD feedstock. The proposed model incorporates key cost factors such as material preparation, compaction, and processing efficiency. A case study is conducted to compare the cost of upcycled feedstock with commercially available AFSD feedstock, providing insights into the economic feasibility of chip upcycling for AFSD applications.
{"title":"An activity-based parametric cost analysis for upcycling machining chips to produce feedstock for sustainable additive friction stir deposition","authors":"Sweta Baruah, Joshua Hoekstra, Tony Schmitz","doi":"10.1016/j.addlet.2025.100288","DOIUrl":"10.1016/j.addlet.2025.100288","url":null,"abstract":"<div><div>With the growing emphasis on supply chain resilience and efficiency, manufacturers are increasingly exploring sustainable material reuse strategies. One promising approach is the upcycling of machining chips into usable feedstock for additive friction stir deposition (AFSD), a solid-state additive manufacturing process. AFSD has demonstrated potential for integrating into hybrid manufacturing workflows, offering advantages such as reduced material waste and enhanced process sustainability. However, for chip upcycling to produce AFSD feedstock to be viable, its production cost must be accurately assessed and compared to conventional feedstock options. Estimating these costs poses challenges due to the complexity of the upcycling process and its associated variables. This paper presents a cost modeling framework for the production of upcycled bars from machining chips, specifically as AFSD feedstock. The proposed model incorporates key cost factors such as material preparation, compaction, and processing efficiency. A case study is conducted to compare the cost of upcycled feedstock with commercially available AFSD feedstock, providing insights into the economic feasibility of chip upcycling for AFSD applications.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"14 ","pages":"Article 100288"},"PeriodicalIF":4.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143935863","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 : 2025-07-01Epub Date: 2025-05-08DOI: 10.1016/j.addlet.2025.100286
Kayah St. Germain , Damien Marchand , Laurence Chocinski-Arnault , Hani E. Naguib , Fabienne Touchard
Material extrusion 3D printing is an up-and-coming additive manufacturing method that is continuously being explored for its many benefits including rapid prototyping, high degree of customizability, and low material waste production, among others. One of the most widely used materials in material extrusion 3D printing is polylactic acid (PLA) due to its ease of printability and bio-origins. Recently, new biofiller reinforced PLA biocomposite filaments have begun being sold commercially, but the introduction of the biofiller creates problems of increased hydrophilicity and hygroscopicity. In this study, a possible solution to this problem was explored by using multimaterial 3D printing to add a thin, structured outer layer to the biocomposite in either pure PLA or TPU. This layer helps limit any external moisture from coming into contact with the underlying biocomposite by creating a barrier with increased hydrophobicity. A grid, triangle, and honeycomb pattern were each tested at 50 %, 75 %, and 100 % pattern densities for each material. It was found that, along with the pattern that was printed, the filament deposition process created additional roughness that influenced the way the water droplets interacted with the surface. All the patterned surfaces displayed a higher water contact angle than when the material was printed in a flat manner. Additionally, factors that influence the feasibility of using this outer structured layer to improve the surface hydrophobicity of biocomposite parts were explored, including material compatibility and adhesion.
{"title":"Multimaterial 3D printing of structured surfaces for increased hydrophobicity of biocomposite materials","authors":"Kayah St. Germain , Damien Marchand , Laurence Chocinski-Arnault , Hani E. Naguib , Fabienne Touchard","doi":"10.1016/j.addlet.2025.100286","DOIUrl":"10.1016/j.addlet.2025.100286","url":null,"abstract":"<div><div>Material extrusion 3D printing is an up-and-coming additive manufacturing method that is continuously being explored for its many benefits including rapid prototyping, high degree of customizability, and low material waste production, among others. One of the most widely used materials in material extrusion 3D printing is polylactic acid (PLA) due to its ease of printability and bio-origins. Recently, new biofiller reinforced PLA biocomposite filaments have begun being sold commercially, but the introduction of the biofiller creates problems of increased hydrophilicity and hygroscopicity. In this study, a possible solution to this problem was explored by using multimaterial 3D printing to add a thin, structured outer layer to the biocomposite in either pure PLA or TPU. This layer helps limit any external moisture from coming into contact with the underlying biocomposite by creating a barrier with increased hydrophobicity. A grid, triangle, and honeycomb pattern were each tested at 50 %, 75 %, and 100 % pattern densities for each material. It was found that, along with the pattern that was printed, the filament deposition process created additional roughness that influenced the way the water droplets interacted with the surface. All the patterned surfaces displayed a higher water contact angle than when the material was printed in a flat manner. Additionally, factors that influence the feasibility of using this outer structured layer to improve the surface hydrophobicity of biocomposite parts were explored, including material compatibility and adhesion.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"14 ","pages":"Article 100286"},"PeriodicalIF":4.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070317","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 : 2025-07-01Epub Date: 2025-05-28DOI: 10.1016/j.addlet.2025.100290
Christopher A. Hareland , Maria-Ioanna T. Tzini , Florian Hengsbach , Gregory B. Olson , Peter W. Voorhees
We present a fully general model for the columnar-to-equiaxed transition (CET) that extends the classical mechanical blocking models to completely arbitrary nucleation-undercooling distributions and dendrite growth laws. The general approach is compared to the classical models for a recently reported die steel developed for additive manufacturing (AM). Notably, the models employ a completely pre-characterized and physically motivated set of material parameters, i.e., the kinetic coefficients and nucleation parameters. A method of calculating the nucleation parameters using CALPHAD (CALculation of PHAse Diagrams) software is also demonstrated and discussed. The general model can directly utilize this full distribution of nucleation parameters, as well as the full dendrite growth law obtained from a CALPHAD-coupled model that incorporates non-equilibrium kinetic effects in multicomponent alloys. Finally, a morphology selection map is constructed for the printable die steel to predict regions of equiaxed dendritic, columnar dendritic, and plane-front solidification, showing that the general model of the CET provides higher fidelity in predicting regions of columnar and equiaxed solidification, and that tailoring the inoculant particle-size distribution is a viable method of controlling the CET under AM processing conditions.
{"title":"A generalized mechanical blocking criterion for the columnar-to-equiaxed transition during additive manufacturing","authors":"Christopher A. Hareland , Maria-Ioanna T. Tzini , Florian Hengsbach , Gregory B. Olson , Peter W. Voorhees","doi":"10.1016/j.addlet.2025.100290","DOIUrl":"10.1016/j.addlet.2025.100290","url":null,"abstract":"<div><div>We present a fully general model for the columnar-to-equiaxed transition (CET) that extends the classical mechanical blocking models to completely arbitrary nucleation-undercooling distributions and dendrite growth laws. The general approach is compared to the classical models for a recently reported die steel developed for additive manufacturing (AM). Notably, the models employ a completely pre-characterized and physically motivated set of material parameters, i.e., the kinetic coefficients and nucleation parameters. A method of calculating the nucleation parameters using CALPHAD (CALculation of PHAse Diagrams) software is also demonstrated and discussed. The general model can directly utilize this full distribution of nucleation parameters, as well as the full dendrite growth law obtained from a CALPHAD-coupled model that incorporates non-equilibrium kinetic effects in multicomponent alloys. Finally, a morphology selection map is constructed for the printable die steel to predict regions of equiaxed dendritic, columnar dendritic, and plane-front solidification, showing that the general model of the CET provides higher fidelity in predicting regions of columnar and equiaxed solidification, and that tailoring the inoculant particle-size distribution is a viable method of controlling the CET under AM processing conditions.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"14 ","pages":"Article 100290"},"PeriodicalIF":4.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144205493","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 : 2025-07-01Epub Date: 2025-05-02DOI: 10.1016/j.addlet.2025.100285
Tyler D. Smith, Dhruv Bhate
This study investigates a novel approach using thermodynamic first principles for optimizing the design of a cellular material for requirements-driven multi-physics, multi-objective optimization. To accomplish this, a generalizable multi-objective optimization method was developed to minimize total exergy destruction as a result of any number of irreversibilities quantified at the level of the unit-cell topology. The method was demonstrated by optimizing the topology of a regular honeycomb to minimize irreversibilities due to thermal losses, fluid friction, mechanical strength, and mass. Using this approach, the method was able to quantitatively optimize the design to minimize thermodynamic irreversibilities and qualitatively understand the interaction between multiple, or individual objective functions to optimize systems for specific use cases. Furthermore, the Relative Exergy Destruction number was proposed as a systematic method for assessing design trade-offs by evaluating the relative contribution of each irreversibility quantified in the optimization.
{"title":"Toward an Entropy-based Method for Multi-Physics Optimization of Additively Manufactured Cellular Materials","authors":"Tyler D. Smith, Dhruv Bhate","doi":"10.1016/j.addlet.2025.100285","DOIUrl":"10.1016/j.addlet.2025.100285","url":null,"abstract":"<div><div>This study investigates a novel approach using thermodynamic first principles for optimizing the design of a cellular material for requirements-driven multi-physics, multi-objective optimization. To accomplish this, a generalizable multi-objective optimization method was developed to minimize total exergy destruction as a result of any number of irreversibilities quantified at the level of the unit-cell topology. The method was demonstrated by optimizing the topology of a regular honeycomb to minimize irreversibilities due to thermal losses, fluid friction, mechanical strength, and mass. Using this approach, the method was able to quantitatively optimize the design to minimize thermodynamic irreversibilities and qualitatively understand the interaction between multiple, or individual objective functions to optimize systems for specific use cases. Furthermore, the Relative Exergy Destruction number was proposed as a systematic method for assessing design trade-offs by evaluating the relative contribution of each irreversibility quantified in the optimization.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"14 ","pages":"Article 100285"},"PeriodicalIF":4.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143935864","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 : 2025-07-01Epub Date: 2025-05-15DOI: 10.1016/j.addlet.2025.100291
Vivek K Sahu , Hector R. Siller , M.H. Herman Shen
The present study examines the effect of HIP (Hot Isostatic Pressing) treatment above the β-transus temperature on porosity reduction and its effect on the transition from columnar to equiaxed prior β-grains in L-PBF (Laser Powder Bed Fusion) Ti6Al4V. HIP treatment was conducted at a holding temperature of 1050 °C and a pressure of 120 MPa for 2 h on the L-PBF Ti6Al4V samples, which were deposited with four different scanning speeds of 300 mm/s, 400 mm/s, 650 mm/s, and 1100 mm/s, while keeping the other deposition parameters constant. The sample with the higher scanning speed (1100 mm/s) exhibits the highest area fraction of lack-of-fusion defects, leading to more pronounced equiaxed β-grain refinement and texture weakening compared to the sample that has the lowest scanning speed (300 mm/s) and negligible lack-of-fusion defect. During the HIP treatment, the local stresses around the sharp tips of the defects, along with the inherent residual stresses in the as-built samples, contribute to the dynamic recrystallization below and above the β-transus temperature.
{"title":"Effectiveness of residual stress and pores on the β-grain refinement in L-PBF Ti6Al4V processed with hot isostatic pressing","authors":"Vivek K Sahu , Hector R. Siller , M.H. Herman Shen","doi":"10.1016/j.addlet.2025.100291","DOIUrl":"10.1016/j.addlet.2025.100291","url":null,"abstract":"<div><div>The present study examines the effect of HIP (Hot Isostatic Pressing) treatment above the β-transus temperature on porosity reduction and its effect on the transition from columnar to equiaxed prior β-grains in L-PBF (Laser Powder Bed Fusion) Ti6Al4V. HIP treatment was conducted at a holding temperature of 1050 °C and a pressure of 120 MPa for 2 h on the L-PBF Ti6Al4V samples, which were deposited with four different scanning speeds of 300 mm/s, 400 mm/s, 650 mm/s, and 1100 mm/s, while keeping the other deposition parameters constant. The sample with the higher scanning speed (1100 mm/s) exhibits the highest area fraction of lack-of-fusion defects, leading to more pronounced equiaxed β-grain refinement and texture weakening compared to the sample that has the lowest scanning speed (300 mm/s) and negligible lack-of-fusion defect. During the HIP treatment, the local stresses around the sharp tips of the defects, along with the inherent residual stresses in the as-built samples, contribute to the dynamic recrystallization below and above the β-transus temperature.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"14 ","pages":"Article 100291"},"PeriodicalIF":4.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144134287","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 : 2025-07-01Epub Date: 2025-08-13DOI: 10.1016/j.addlet.2025.100317
Andrew B. Kustas , Erin Barrick , Jonathan Pegues , Hannah Sims , Mary L. Gucik , Michael Melia , Alexander E. Wilson-Heid , Joshua D. Sugar , Eric D. Hintsala , Kevin M. Schmalbach , Frank W. DelRio , Tyler LeBrun
Tantalum (Ta) is a refractory metal with excellent corrosion resistance and biocompatability, high melting temperature and density, and good electrical and thermal conductivity, with applications in capacitors, medical implants and devices, linings in the chemical industry, penetrator projectiles, and nuclear reactors. In this work, we examined the mechanical isotropy and corrosion behavior of tantalum produced through laser beam powder bed fusion (PBF-LB). Electron backscatter diffraction (EBSD), tensile tests, nanoindentation, and environmental and galvanic corrosion tests were utilized to establish structure-property relationships as a function of orientation, temperature, and pH. EBSD showed the horizontal and vertical orientations had different grain size distributions and weak texture. From tensile testing, PBF-LB Ta exhibited comparable strain-at-failure relative to wrought Ta, with significantly higher yield and ultimate strengths relative to ASTM B708. Room-temperature nanoindentation confirmed weak mechanical anisotropy via complementary EBSD images and showed small variations in reduced modulus and hardness after annealing to 800 °C due to oxide formation. The environmental corrosion tests in HCl (acid), NaCl (neutral), and KOH (basic) suggested the corrosion current density for PBF-LB Ta was lower than wrought, signifying slower corrosion for PBF-LB Ta. The passive nature of PBF-LB and wrought Ta was observed during galvanic corrosion; when coupled with titanium, aluminum, or stainless steel, most systems did not show corrosion after 24 hr. In all, the results showed that PBF-LB Ta has comparable or, in some cases, superior mechanical and corrosion properties to wrought Ta.
{"title":"On the mechanical isotropy and corrosion behavior of tantalum produced via laser beam powder bed fusion","authors":"Andrew B. Kustas , Erin Barrick , Jonathan Pegues , Hannah Sims , Mary L. Gucik , Michael Melia , Alexander E. Wilson-Heid , Joshua D. Sugar , Eric D. Hintsala , Kevin M. Schmalbach , Frank W. DelRio , Tyler LeBrun","doi":"10.1016/j.addlet.2025.100317","DOIUrl":"10.1016/j.addlet.2025.100317","url":null,"abstract":"<div><div>Tantalum (Ta) is a refractory metal with excellent corrosion resistance and biocompatability, high melting temperature and density, and good electrical and thermal conductivity, with applications in capacitors, medical implants and devices, linings in the chemical industry, penetrator projectiles, and nuclear reactors. In this work, we examined the mechanical isotropy and corrosion behavior of tantalum produced through laser beam powder bed fusion (PBF-LB). Electron backscatter diffraction (EBSD), tensile tests, nanoindentation, and environmental and galvanic corrosion tests were utilized to establish structure-property relationships as a function of orientation, temperature, and pH. EBSD showed the horizontal and vertical orientations had different grain size distributions and weak texture. From tensile testing, PBF-LB Ta exhibited comparable strain-at-failure relative to wrought Ta, with significantly higher yield and ultimate strengths relative to ASTM <span><span>B708</span><svg><path></path></svg></span>. Room-temperature nanoindentation confirmed weak mechanical anisotropy via complementary EBSD images and showed small variations in reduced modulus and hardness after annealing to 800 °C due to oxide formation. The environmental corrosion tests in HCl (acid), NaCl (neutral), and KOH (basic) suggested the corrosion current density for PBF-LB Ta was lower than wrought, signifying slower corrosion for PBF-LB Ta. The passive nature of PBF-LB and wrought Ta was observed during galvanic corrosion; when coupled with titanium, aluminum, or stainless steel, most systems did not show corrosion after 24 hr. In all, the results showed that PBF-LB Ta has comparable or, in some cases, superior mechanical and corrosion properties to wrought Ta.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"14 ","pages":"Article 100317"},"PeriodicalIF":4.7,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144863264","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 : 2025-07-01Epub Date: 2025-07-24DOI: 10.1016/j.addlet.2025.100312
Minsol Park, Mudit Kesharwani, Mohammad Attarian Shandiz, Mathieu Brochu
This study investigates the effectiveness of heat treatment (HT) to homogenize the microstructural and mechanical asymmetry between the bulk and the downskin regions of support-free IN718 walls fabricated at angles of 30°, 20°, 15°, and 10° In the as-built condition, the microhardness ranged from 340 ± 5 HV to 351 ± 4 HV for the bulk and from 315 ± 4 HV to 323 ± 10 HV for the downskin region, resulting in a maximum difference range of 35 HV. The HT eliminated this difference where microhardness values of 482 ± 3 HV in the bulk and 478 ± 4 HV in the downskin were measured. The HT induced γ″ precipitation with volume fraction and mean precipitate size in the bulk of 16.6 % and 24.7 ± 7.3 nm. These values are statistically comparable to those in the downskin: 15.8 % and 26.5 ± 7.9 nm. The similarity in the γ″ characteristics explains the recovery of the mismatch in hardness as γ″ contributes approximately 85 % of the strengthening in the HT condition.
{"title":"Microstructure homogenization of laser powder bed fusion support-free low angle IN718 walls through heat treatment","authors":"Minsol Park, Mudit Kesharwani, Mohammad Attarian Shandiz, Mathieu Brochu","doi":"10.1016/j.addlet.2025.100312","DOIUrl":"10.1016/j.addlet.2025.100312","url":null,"abstract":"<div><div>This study investigates the effectiveness of heat treatment (HT) to homogenize the microstructural and mechanical asymmetry between the bulk and the downskin regions of support-free IN718 walls fabricated at angles of 30°, 20°, 15°, and 10° In the as-built condition, the microhardness ranged from 340 ± 5 HV to 351 ± 4 HV for the bulk and from 315 ± 4 HV to 323 ± 10 HV for the downskin region, resulting in a maximum difference range of 35 HV. The HT eliminated this difference where microhardness values of 482 ± 3 HV in the bulk and 478 ± 4 HV in the downskin were measured. The HT induced γ″ precipitation with volume fraction and mean precipitate size in the bulk of 16.6 % and 24.7 ± 7.3 nm. These values are statistically comparable to those in the downskin: 15.8 % and 26.5 ± 7.9 nm. The similarity in the γ″ characteristics explains the recovery of the mismatch in hardness as γ″ contributes approximately 85 % of the strengthening in the HT condition.</div></div>","PeriodicalId":72068,"journal":{"name":"Additive manufacturing letters","volume":"14 ","pages":"Article 100312"},"PeriodicalIF":4.7,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144722265","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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