Article
Optics
K. Hareharen, S. Pradeep Kumar, T. Panneerselvam, P. Dinesh Babu, N. Sriraman
Summary: Selective Laser Melting (SLM) is an emerging additive manufacturing technology that allows highly customized metallic parts. However, the poor tribological performance of stainless steel 316L in the as-printed condition limits its applications. This study applies laser shock peening (LSP), a surface modification technique, to SLM-made SS 316L to improve its micro-structure, mechanical properties, and wear behavior. Results show that LSP promotes micro-level grain refinement and compressive residual stresses, resulting in increased micro-hardness and enhanced wear resistance.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
W. W. Deng, H. F. Lu, Y. H. Xing, K. Y. Luo, J. Z. Lu
Summary: The effects of build direction and laser shock peening on the properties and microstructure of 316L stainless steel were investigated. The results showed that the strength and ductility of the stainless steel varied under different build angles and LSP treatments, with the sample fabricated at a 90-degree build angle and subjected to LSP having the best combination of strength and ductility.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Chemistry, Physical
Zhibin An, Weifeng He, Xin Zhou, Liucheng Zhou, Xiangfan Nie
Summary: This study found that after LSP treatment, a compressive stress layer was formed on the surface of laser-melted parts, the microhardness was increased, and the misorientation and dislocation features were observed which contributed to the improvement of fatigue performance. The LMD+LSPned samples showed a 61% improvement in high cycle fatigue performance compared to only LMD samples.
Article
Optics
Gang Xu, Haifei Lu, Kaiyu Luo, Fengze Dai, Jinzhong Lu
Summary: This study investigates the effect of surface curvature on residual stress in laser shock peened 316L stainless steel specimens, comparing the results of convex and concave surfaces using experimental and theoretical methods. The research found that increasing surface curvature leads to a decrease in compressive residual stress and has a significant influence on the thickness of the plastic deformation layer. Additionally, a mathematical model was proposed to predict the compressive residual stress fields on curved surfaces after laser shock peening.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Materials Science, Coatings & Films
Sanin Zulic, Danijela Rostohar, Jan Kaufman, Sunil Pathak, Jaromir Kopecek, Marek Bohm, Jan Brajer, Tomas Mocek
Summary: This study investigates the fatigue life behavior of additively manufactured stainless steel 316L in a laser shock peening process, and finds that LSP operations can significantly improve residual stresses and fatigue life.
SURFACE ENGINEERING
(2022)
Article
Engineering, Mechanical
Barbara Rivolta, Riccardo Gerosa, Davide Panzeri
Summary: In additive manufacturing, surface finishing and porosities remain detrimental variables to fatigue strength. However, removing defects near the surface is expected to significantly improve fatigue strength. This study performed fully-reversed rotating-bending fatigue tests on SLMed 316L in both as-built and machined conditions, and discussed fatigue failures using the Kitagawa-Takahashi diagram. The fatigue stress was related to the equivalent micro-notch length of the killer defect in each condition. This work also analyzed the possibility of predicting fatigue limits at 50% probability based on the equivalent micro-notch length.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Chemistry, Physical
Zhentao Wang, Shanglei Yang, Yubao Huang, Cong Fan, Zeng Peng, Zihao Gao
Summary: Based on the study, fatigue cracks in SLM-316L mainly occur due to defects, and the cracks exhibit Z-shaped propagation after initiation.
Article
Chemistry, Physical
Timo Rautio, Matias Jaskari, Tejas Gundgire, Terho Iso-Junno, Minnamari Vippola, Antti Jarvenpaa
Summary: Severe shot peening (SSP) as a post-processing technique significantly improves the surface features and mechanical properties of additive manufactured 316L, including increased residual stress, improved surface hardness and material strength, as well as enhanced fatigue limit and fatigue strength.
Article
Optics
Fengze Dai, Wei Cheng, Yueyang Zheng, Xizhang Chen
Summary: After treatment with laser shock peening technology, the rolling contact fatigue performance of 316 stainless steel has been significantly improved, mainly due to the induction of high amplitude compressive residual stress on the surface layer. In addition, the treated 316 stainless steel is sensitive to contact stress.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Yandong Jing, Xuewei Fang, Naiyuan Xi, Xianlu Feng, Ke Huang
Summary: The study on the effect of laser shock peening (LSP) on 7050 aluminum alloy and 316L stainless steel revealed that no grain refinement was observed regardless of the laser cycles and energy density, but there was an increase in dislocation density. Tensile tests showed that the yield strength of both materials was improved after the LSP process, albeit sacrificing elongations. A potential method to calculate the dynamic yield stress of metallic materials was proposed with the help of the LSP process.
MATERIALS CHARACTERIZATION
(2021)
Article
Chemistry, Physical
Zdenek Pitrmuc, Jan Simota, Libor Beranek, Petr Mikes, Vladislav Andronov, Jiri Sommer, Frantisek Holesovsky
Summary: This paper provides an in-depth analysis of the mechanical and microstructural properties of AISI 316L austenitic stainless steel produced by laser powder bed fusion (LPBF) additive manufacturing technology. The study investigates the anisotropy of mechanical and microstructural properties in relation to the built orientation and direction of loading, as well as the influence of the process parameter focus level on mechanical properties. The evaluation of properties was done using various tests and analysis techniques, which confirmed the high quality of the LPBF additive manufactured material. Additionally, microstructural investigation revealed the outstanding characteristics of the material.
Article
Nanoscience & Nanotechnology
Yefeng Chen, Xiaowei Wang, Jiawei Shen, Yawei Peng, Yong Jiang, Xinyu Yang, Sean B. Leen, Jianming Gong
Summary: By conducting low cycle fatigue (LCF) tests on SLM 316L and traditional 316L, it has been found that SLM 316L exhibits stable cyclic softening behavior and higher fatigue life compared to traditional 316L. This is attributed to its higher strength as well as the coarsening of cellular sub-structure, evolution of geometrically necessary dislocations (GND), and influence of texture direction.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
Siqi Chen, Guoqiang Ma, Guilin Wu, Andrew Godfrey, Tianlin Huang, Xiaoxu Huang
Summary: The microstructure and chemical composition of 316L stainless steel prepared by selective laser melting were characterized. The study showed the presence of a multi-scale microstructure with equiaxed and columnar grains, dislocation cell blocks, individual dislocations, and nanosized particles. The misorientations across dislocation cells were determined, and the distribution of alloying elements and nitrogen content was also observed. The study found that dislocation strengthening and solid solution strengthening were the main contributing factors to the yield strength of the material.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Engineering, Manufacturing
Changgong Kim, Houshang Yin, Andrii Shmatok, Barton C. Prorok, Xiaoyuan Lou, Kathryn H. Matlack
Summary: Additive manufacturing (AM) has the potential to revolutionize manufacturing by fabricating complex geometries, but faces challenges in quality assessment. This study demonstrates the use of ultrasonic phase velocity measurements to evaluate defects and microstructural differences in AM stainless steel 316L parts, showing sensitivity to pore geometry and texture. The research suggests that the measured ultrasonic phase velocity is sensitive to changes in anisotropic elastic constants in AM materials.
ADDITIVE MANUFACTURING
(2021)
Article
Optics
S. Herenu, R. Strubbia, C. Rubio-Gonzalez, L. Spadaro, R. Bolmaro, G. Gomez-Rosas
Summary: The study shows that laser shock peening without coating (LSPwC) can enhance the high cycle life (HCF) of superferritic stainless steels, especially with higher pulse density, resulting in more pronounced fatigue life improvement.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Engineering, Civil
Lorenzo Del Giudice, Rafal Wrobel, Antonios A. Katsamakas, Christian Leinenbach, Michalis F. Vassiliou
Summary: Global level assumptions in numerical models are identified as a major source of error in modeling Reinforced Concrete (RC) structures, suggesting the importance of statistical validation through small-scale testing with additive manufacturing for reinforcement fabrication. Experimental results on scaled RC cantilever members show the effectiveness of the proposed approach in capturing the cyclic response of RC members, indicating the potential use of small-scale specimens for statistical validation of numerical model assumptions.
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS
(2022)
Article
Materials Science, Multidisciplinary
C. Sofras, J. Capek, A. Arabi-Hashemi, C. Leinenbach, M. Frost, K. An, R. E. Loge, M. Strobl, E. Polatidis
Summary: This study investigates the manipulation of crystallographic texture in austenitic stainless steels using laser-powder bed fusion (L-PBF) to tailor their deformation behavior. By adjusting laser power and scanning speed, tailored crystallographic textures can be obtained. The influence of crystallographic texture on deformation behavior is demonstrated, and the asymmetry between tension and compression is discussed.
MATERIALS & DESIGN
(2022)
Article
Nanoscience & Nanotechnology
Hossein Ghasemi-Tabasi, MargauxN. D. Larcher, Cyril Cayron, Jamasp Jhabvala, Steven Van Petegem, Nikola E. Kalentics, Eric Boillat, Roland Loge
Summary: The impact of phase transformation and stress state on the manufacturing and crystallographic properties of red-gold alloys in the printing and heat treatment processes is investigated.
SCRIPTA MATERIALIA
(2022)
Article
Nanoscience & Nanotechnology
Maryam Mohri, Irene Ferretto, Christian Leinenbach, Dohyung Kim, Dimitrios G. Lignos, Elyas Ghafoori
Summary: This study systematically investigated the effects of heat and thermomechanical treatments on the pseudo-elastic behavior of an Fe-based shape-memory alloy. The results showed that decreasing the grain size and precipitation of VCs resulted in an improved pseudo-elasticity. The thermomechanical treatment decreased the number of thermal twins and developed a [111] texture in the austenite phase, which reduced the critical stress for inducing martensite.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
I. Ferretto, D. Kim, M. Mohri, E. Ghafoori, W. J. Lee, C. Leinenbach
Summary: A Fe-Mn-Si shape memory alloy containing V and C was successfully fabricated by laser powder bed fusion. After aging treatment, the alloy exhibits pronounced pseudo-elasticity due to the development of fine microstructure and the evaporation of Mn. The formation of high precipitate densities also contributes to the improved thermo-mechanical properties.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Chemistry, Physical
Manuel Ortega Varela de Seijas, Andreas Bardenhagen, Thomas Rohr, Enrico Stoll
Summary: Indirect induction heating is proposed as an effective method to densify Fused Filament Fabricated (FFF) parts, achieving high densities without the need for part transportation. This simplifies the processing of metal parts produced through material extrusion additive manufacturing.
Article
Engineering, Manufacturing
Manuel Ortega Varela de Seijas, Andreas Bardenhagen, Laurent Pambaguian, Enrico Stoll
Summary: A novel cost effective method for additive manufacturing of metals and ceramics uses filaments embedded with powdered granules. The debinding process, which is time-consuming and requires toxic agents, is improved by using a low intensity infra-red laser to remove the binder matrix layer by layer. The debinding time is significantly reduced compared to traditional methods, and defects and roughness are minimized.
JOURNAL OF MANUFACTURING PROCESSES
(2023)
Article
Engineering, Manufacturing
Viktor Lindstrom, Giandomenico Lupo, Jian Yang, Vladyslav Turlo, Christian Leinenbach
Summary: This study proposes a simple thermal scaling model for predicting the transition from balling mode to conduction mode in laser powder bed fusion. The model's accuracy and reliability are verified through experiments and simulations, and it suggests viable strategies for adjusting the operating parameters to achieve defect-free 3D printed parts.
ADDITIVE MANUFACTURING
(2023)
Article
Materials Science, Multidisciplinary
M. Busi, E. Polatidis, C. Sofras, P. Boillat, A. Ruffo, C. Leinenbach, M. Strobl
Summary: Non-destructive characterization methods play a crucial role in studying the mechanism of phase transformations in materials. In this study, a non-destructive technique using polarized neutrons is introduced to quantitatively map the spatial distribution of magnetic phases.
MATERIALS TODAY ADVANCES
(2022)
Article
Materials Science, Multidisciplinary
I. Ferretto, D. Kim, W. J. Lee, E. Hosseini, N. M. della Ventura, A. Sharma, C. Sofras, J. Capek, E. Polatidis, C. Leinenbach
Summary: The fcc-c-, hcp-e-, and bcc-a' martensitic transformation of a Fe-Mn-Si-based shape memory alloy fabricated by laser powder bed fusion (LPBF) is studied for the first time. Comparison between horizontal and vertical specimens shows that sample orientation considerably influences the alloy's shape memory and mechanical properties. The reason for this variation is found in the distinct crystallographic texture generated during the LPBF process.
MATERIALS & DESIGN
(2023)
Article
Engineering, Manufacturing
R. Wrobel, P. Gh Ghanbari, X. Maeder, E. Hosseini, C. Leinenbach
Summary: Laser powder bed fusion technology has the potential to fabricate complex geometries with improved functionality, especially when combined with nickel alloys like Hastelloy X for high-temperature applications. However, little is known about the LPBF fabrication of fine structures with thin walls, and this study shows that wall thickness plays an important role in microstructure formation.
PROGRESS IN ADDITIVE MANUFACTURING
(2023)
Article
Computer Science, Information Systems
Neils Vilchez, Manuel Ortega Varela de Seijas, Andreas Bardenhagen, Thomas Rohr, Enrico Stoll
Summary: This article describes a novel induction heater that efficiently tailors temperature profiles to densify MEAM powder compacts. It operates by heating a graphite crucible, achieving in situ sintering within the same device. With a resonant frequency of 62.86 kHz, it provides a penetration depth of 2.01 mm and a crucible temperature of 1365.7°C with only 1.313 kW consumption, increasing efficiency compared to low-cost systems. Equipped with a feedback circuit, it offers five distinct control techniques to self-tune the crucible temperature.
Article
Materials Science, Multidisciplinary
M. Ortega Varela de Seijas, A. Bardenhagen, T. Rohr, E. Stoll
Summary: To date, the debinding and sintering of parts fabricated through MEX have been done in a time-consuming and disconnected approach. This study introduces a hybrid device that combines MEX with local debinding and sintering, enabling the removal of binder matrix and sintering within the same volume efficiently. The results show promising improvements compared to conventional methods, with simplified processing and avoidance of toxic agents and expensive post-processing equipment.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Engineering, Manufacturing
Anthony De Luca, Christoph Kenel, David C. Dunand, Christian Leinenbach
Summary: The effects of adding 1 wt% HfO2 nano-dispersoids on the microstructure of a high-y' Ni-8.5Cr-5.5Al-1Ti model superalloy manufactured via laser-based powder-bed fusion are investigated. HfO2 dispersoids, despite their high melting point, are not fully stable in the melt pool. At the nanoscale, the superalloy grains contain various Hf-Al-O, Hf-O, and Hf-S-rich nano-dispersoids, as well as y' L12-Ni3Hf nano-precipitates, indicating reaction of HfO2 dispersoids during melting. Also, Hf-Al-O-rich slag inclusions with a two-phase HfO2-Al2O3 eutectic structure are observed at the meso-scale. Macroscopic cracks form at the boundaries of the highly textured grains, suggesting solidification cracking.
ADDITIVE MANUFACTURING LETTERS
(2023)
Article
Engineering, Manufacturing
I. Ferretto, A. Borzi, D. Kim, N. M. Della Ventura, E. Hosseini, W. J. Lee, C. Leinenbach
Summary: The present study demonstrates the possibility of microstructure modification via process parameter variation on a Fe-Mn-Si based shape memory alloy fabricated by laser powder bed fusion. Different microstructures and phase fractions can be achieved by varying the scan speed and Mn evaporation, and a direct correlation between the generated microstructure and achieved mechanical and shape memory properties is found.
ADDITIVE MANUFACTURING LETTERS
(2022)
Article
Engineering, Manufacturing
Przemyslaw Golebiewski, Pawel Wienclaw, Jaroslaw Cimek, Pawel Socha, Dariusz Pysz, Adam Filipkowski, Grzegorz Stepniewski, Olga Czerwinska, Ireneusz Kujawa, Ryszard Stepien, Rafal Kasztelanic, Andrzej Burgs, Ryszard Buczynski
Summary: We report the development of a 3D printing process for producing soft glass optical fibers. The process involves direct printing using a miniaturized crucible and depositing straight horizontally-oriented lines to replace traditional assembly techniques. Experimental results demonstrate good performance of the printed photonic crystal fiber preform.
ADDITIVE MANUFACTURING
(2024)
