Article
Automation & Control Systems
Subin Shrestha, Kevin Chou
Summary: The study examines the effects of laser parameters on single-track geometry and porosity in selective laser melting, showing that an increase in LED results in higher porosity. Metallography reveals a significant increase in melt pool depth with LED increase, indicating a change in melting mode.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
I. A. Pelevin, D. Yu. Ozherelkov, S. V. Chernyshikhin, A. Yu. Nalivaiko, A. A. Gromov, V. B. Chzhan, E. A. Terekhin, I. S. Tereshina
Summary: Single tracks of Nd2Fe14B powder were obtained through selective laser melting. The melting features of the material under laser irradiation were analyzed, and the optimal printing parameters were determined.
Article
Materials Science, Multidisciplinary
Tian Yang, Zhijian Feng, Yating Qiu, Wei Han, Lingbao Kong
Summary: This paper explores the benefits and possibilities of using irregular shaped powder in selective laser melting (SLM) of glass. Through a series of experiments, it is demonstrated that irregularly-shaped glass powder can be successfully used in the SLM process and that process parameter changes can yield builds with comparable porosity levels to builds using typical spherical powder.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Nanoscience & Nanotechnology
Hyungsoo Lee, Joong Eun Jung, Dong-Soo Kang, Hi Won Jeong, Dae Won Yun, Jungho Choe, Young Soo Yoo, Seong-Moon Seo
Summary: This study investigated the effects of powder reuse on the microstructures and mechanical properties of selective laser melted (SLM) parts. It was found that increased powder reuse led to an increase in average particle size and oxidation of the powder, which in turn affected the recrystallization of the SLMed parts. However, in the case of multiple powder reuses, the increased oxidation contributed to improved mechanical properties of the parts.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Engineering, Manufacturing
Dengzhi Yao, Xizhong An, Haitao Fu, Hao Zhang, Xiaohong Yang, Qingchuan Zou, Kejun Dong
Summary: This article studied the spreading of 316L stainless steel powder during printing through 3D particulate scale dynamic simulations, identifying factors affecting powder bed quality and optimized conditions such as blade moving speed and particle size. The simulation results showed that optimal conditions lead to a more uniform and denser powder bed.
ADDITIVE MANUFACTURING
(2021)
Article
Engineering, Chemical
Erlei Li, Zongyan Zhou, Lin Wang, Qijun Zheng, Ruiping Zou, Aibing Yu
Summary: This study investigated the multi-physics interactions between scanning tracks in laser powder bed fusion (LPBF) using a CFD-based model. The results showed that the flow at the head of the first track gradually changed due to the intense centrifugal motion of the second track, causing the combined tracks to spread. The voids between adjacent tracks were compressed by the molten liquid and sealed by the resolidified part, resulting in large pores, especially for medium laser power and hatch space. The liquid phase overlap of unidirectional track was narrower compared to bidirectional scanning. Under the island scanning strategy, the flow direction of the molten liquid changed multiple times and pores tended to be eliminated. This study contributes to a better understanding of the physics involved in the LPBF process.
Article
Engineering, Chemical
Syed Zahid Hussain, Zareena Kausar, Zafar Ullah Koreshi, Shakil R. Sheikh, Hafiz Zia Ur Rehman, Haseeb Yaqoob, Muhammad Faizan Shah, Ahmad Abdullah, Farooq Sher
Summary: This study proposed a model to account for heat from neighboring tracks in selective laser melting (SLM) process and designed a feedback control to regulate the melt pool cross-sectional area, reducing the impact of heat from nearby tracks. By combining the thermal model with the disturbance model, a nonlinear model describing the melt pool evolution was established, and a PID controller was used to minimize the effect of intertrack disturbance on the melt pool area. Simulation results demonstrated that the controller could effectively regulate the desired melt pool area within a short time frame, enhancing the quality of components and reducing defects in the SLM process.
Article
Engineering, Chemical
Marius Hilzenthaler, Luca Bifano, Florian Scherm, Gerhard Fischerauer, Andrea Seemann, Uwe Glatzel
Summary: The study found that after recycling AISI 904L stainless steel powder ten times, the flowability significantly increased, while there were no significant changes in the chemical composition and particle size distribution of the powder. The printed parts maintained comparable density and mechanical properties, indicating excellent recyclability of the powder material.
Article
Engineering, Chemical
Erlei Li, Zongyan Zhou, Lin Wang, Haopeng Shen, Ruiping Zou, Aibing Yu
Summary: This study employs a validated mathematical model to assess the influence of material properties on the selective laser melting process. The results indicate that the solidification rate and mushy zone constant have a significant impact on the formation of pores and surface defects.
Article
Chemistry, Physical
W. P. Li, H. Wang, Y. H. Zhou, Y. Y. Zhu, S. F. Lin, M. Yan, N. Wang
Summary: This study investigates the impact of rare earth element (Y) addition on the selective laser melting (SLM) printability of high Nb-TiAl alloys, improving the quality of printed samples by modifying the surface structure of the powder. Results show that rare earth elements can be effective means to enhance the formability of crack-sensitive materials in laser-based additive manufacturing.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Engineering, Multidisciplinary
Jingchang Li, Longchao Cao, Jie Xu, Shengyi Wang, Qi Zhou
Summary: The study achieved porosity classification based on high-speed melt pool images and developed corresponding intelligent machine learning algorithms. The results show that the proposed method can effectively classify porosity during the SLM process, potentially reducing porosity defects.
Article
Chemistry, Physical
Zachary A. Young, Meelap M. Coday, Qilin Guo, Minglei Qu, S. Mohammad H. Hojjatzadeh, Luis I. Escano, Kamel Fezzaa, Tao Sun, Lianyi Chen
Summary: This study identifies the sources of uncertainty in the selective laser melting (SLM) process and reveals that variations in processing parameters can result in significant changes in the depression zone, melt pool, and spatter behavior. The responses of SLM dynamics to small variations in processing parameters provide valuable insights for understanding the uncertainties in the SLM process.
Article
Nanoscience & Nanotechnology
J. Karimi, C. Suryanarayana, I Okulov, K. G. Prashanth
Summary: This study investigated the effect of remelting on the microstructure and mechanical properties of Ti6Al4V materials fabricated using selective laser melting. The results showed that the number of remeltings significantly influenced the homogenization of the microstructure and mechanical properties of the materials, with an increase in hardness and ultimate tensile strength but a decrease in ductility observed with a higher number of melting steps.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Manufacturing
Matti Lindroos, Tatu Pinomaa, Atte Antikainen, Juha Lagerbom, Joni Reijonen, Tomi Lindroos, Tom Andersson, Anssi Laukkanen
Summary: The study presents a thermomechanical crystal plasticity model for analyzing microscale evolution and residual stress and strain in a single track event of selective laser melting. The model is effective in addressing material properties and complex performance dependent on microstructure scale phenomena.
ADDITIVE MANUFACTURING
(2021)
Article
Materials Science, Multidisciplinary
Evgenii Borisov, Kirill Starikov, Anatoly Popovich, Tatiana Tihonovskaya
Summary: This study investigated the selective laser melting process of two NiTi alloys with different nickel compositions, exploring the effects of technological parameters on alloy density and nickel content. Results showed that adjusting energy density and processing parameters can lead to changes in the amount of nickel carried away by evaporation, impacting the final composition of the samples. Additionally, utilizing multiple laser processing techniques with low-energy parameters can effectively decrease the nickel content in the alloy.
Article
Chemistry, Physical
Felix Meixner, Mohammad Reza Ahmadi, Christof Sommitsch
Summary: Physics-based models are helpful in developing new materials for more efficient power plants in fossil fueled electricity generation. This study develops a model based on classical nucleation theory and diffusion driven growth to predict the shape and distribution of cavities that occur mainly at grain boundaries during high temperature creep. The model's results are validated against experimental specimens and show good agreement, although it fails to represent the complex interlinking of cavities during tertiary creep.
Article
Automation & Control Systems
Benjamin Meier, Fernando Warchomicka, Jelena Petrusa, Paul Angerer, Jaroslaw Wosik, Reinhard Kaindl, Vojislav Petrovic, Wolfgang Waldhauser, Christof Sommitsch
Summary: In addition to process parameters, powder properties have a significant impact on the material properties of parts produced by powder-based additive manufacturing. This study investigates the influence of different powder producers on the density, chemical composition, and mechanical properties of build samples, as well as the effects of atomization process on morphology, particle size distribution, chemical composition, and oxide layers. The results show that density is highly dependent on surface topology, sphericity, and nature of the oxide layer, while tensile properties are influenced by chemical composition and notched bar impact strength is additionally affected by the oxide layer and suspected TiO2 precipitations.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Marina Gontijo, Arnab Chakraborty, Richard F. Webster, Sergiu Ilie, Jakob Six, Sophie Primig, Christof Sommitsch
Summary: The effects of the combined addition of B and Ti, as well as the influence of different strain rates on the hot ductility behavior of low carbon, continuously cast, microalloyed steels were investigated in this study. Increasing the strain rate improved the ductility, especially in the steel with the leanest composition. The steel containing more B and Ti exhibited better hot ductility behavior. The improvements were attributed to the precipitation behavior and the austenite-ferrite phase transformation.
Article
Materials Science, Multidisciplinary
Jelena Petrusa, Benjamin Meier, Gerda Gruenbacher, Wolfgang Waldhauser, Juergen Eckert
Summary: The effects of laser energy density on the relative density and microstructure of cp-TiGd2 fabricated by LB-PBF were studied, and the influence of printing orientation and different surface treatments on surface topography and biocompatibility were investigated. The aim is to develop additive manufacturing process parameters that can achieve full density and satisfactory biocompatibility for cp-TiGd2 as a low-cost alternative to biomedical materials. An optimized process with high density, improved surface roughness, and noncytotoxicity was achieved using a wide range of process parameters.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Chemistry, Physical
Arezoo Ghanbari, Aydin Bordbar-Khiabani, Fernando Warchomicka, Christof Sommitsch, Benyamin Yarmand, Ali Zamanian
Summary: There is a growing trend to replace permanent implants with biodegradable magnesium implants in temporary bone applications. This is due to the similar mechanical properties and biocompatibility of magnesium to bone. However, the rapid degradation rate of magnesium can lead to implant loosening. This study aims to develop a multifunctional multilayer coating to control the degradation behavior.
SURFACES AND INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Elisabeth Hengge, Jakob Ihrenberger, Eva-Maria Steyskal, Ricardo Buzolin, Martin Luckabauer, Christof Sommitsch, Roland Wuerschum
Summary: The synthesis of bulk nanoporous copper from a copper-manganese alloy by electrochemical dealloying and free corrosion, as well as the electrochemical behavior and oxide formation of the dealloyed structures, have been investigated. The nanoporous copper exhibited suppressed reordering processes and the formation of a hybrid composite of copper and manganese oxide on its surface. This unique heterogeneous structure shows potential for applications in energy storage and catalysis.
NANOSCALE ADVANCES
(2023)
Article
Materials Science, Multidisciplinary
Simon Kaar, Daniel Krizan, Reinhold Schneider, Christof Sommitsch
Summary: A new model considering the competing reactions and mechanical stabilization of austenite has been developed for Q&P steels, and a relationship between C-enrichment and austenite stability has been established. The model can accurately predict the phase fractions and mechanical stability of austenite.
Article
Chemistry, Physical
Andreas Drexler, Matthew Galler, Hamdi Elsayed, Rudolf Vallant, Christof Sommitsch
Summary: Knowing the hydrogen distribution and local concentration gradients in ferritic steel components is crucial for hydrogen embrittlement. The diffusion of hydrogen in ferritic steel is affected by trapping sites in the microstructure and charging conditions. The concept of effective diffusion coefficient is used to calculate diffusion depths, but its application is limited due to the variability caused by sub-surface lattice concentration. The theory of hydrogen bulk diffusion is employed to verify the concept and numerical methods are used for solving the diffusion equation.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Materials Science, Multidisciplinary
T. Mairhofer, S. Arneitz, F. Hofer, C. Sommitsch, G. Kothleitner
Summary: Exploring the chemical micro- and nanostructure of metal alloys is crucial for understanding their physical properties. In this study, the influence of heat treatment on the macroscopic magnetic behavior of additive manufactured FeCrCo alloys is investigated. It is found that the heat treatment affects the nanostructure and ferromagnetic properties of the material. This research provides insights for tailoring manufacturing parameters to obtain desired functional materials.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Chemistry, Medicinal
Jayant Iyer, Lucy M. Morgan, Pamela Harrison, Adrian Davis, Andrew Ray, Stefan Mitsche, Ferdinand Hofer, Isha Saraf, Amrit Paudel
Summary: Ball-milling and harsh manufacturing processes can lead to crystal disorder in solid drugs, affecting their stability during storage, transport, and handling. This study investigates the impact of crystal disorder on the autoxidation of Mifepristone (MFP) and develops a predictive stability model. The study highlights the utility of the model in identifying autoxidative instability in non-crystalline and partially crystalline MFP, contributing to the field of material sciences.
JOURNAL OF PHARMACEUTICAL SCIENCES
(2023)
Article
Engineering, Mechanical
Michael Aigner, Massimo Pellizzari, Josef Domitner, Leonel Elizondo, Martina Fischbacher, Ingrun Laubichler, Armin Paar, Maximilian Reiter, Thomas Trickl, Christof Sommitsch
Summary: Work rolls used in hot rolling of steel are subject to severe wear due to multiple factors such as adhesion, abrasion, rolling contact fatigue, thermal fatigue, and tribo-chemical corrosive attack. Wear tests were conducted using a custom-designed roll test rig to simulate the contact conditions in a hot rolling mill. Optical microscopy and scanning electron microscopy (SEM) were used to analyze the wear and damage mechanisms. Graphitic high-speed steels (G-HSS) with different fractions and types of carbides were investigated, and it was found that MC and M2C/M6C mainly influenced the wear behavior of G-HSS. The optimal balance of carbide types, graphite content, and metal matrix was identified as crucial for achieving high wear performance of work roll materials.
Article
Materials Science, Multidisciplinary
Valerie Sue Goettgens, Lukas Kaserer, Jakob Braun, Ilse Letofsky-Papst, Stefan Mitsche, Gerhard Leichtfried
Summary: In this study, Ti-6Al-4V was alloyed with 15 wt% Cu using laser powder bed fusion (LPBF) to investigate the impact of Cu as a eutectoid alloying element on microstructural features. The in situ alloying resulted in chemical inhomogeneities, enabling simultaneous solidification of different compositions. The resulting microstructure was characterized by metastable, equiaxed 8-Ti and Ti2Cu precipitates, as well as incompletely melted Ti-6Al-4V powder particles and nano-sized alpha crystals. The study demonstrates that Cu is a versatile alloying element, significantly influencing the microstructural development of Ti-6Al-4V.
Article
Chemistry, Physical
Andreas Drexler, Florian Konert, Oded Sobol, Michael Rhode, Josef Domitner, Christof Sommitsch, Thomas Boellinghaus
Summary: This study investigates the detrimental effects of high-pressure hydrogen gas on metals, focusing on understanding the mechanisms and driving forces of hydrogen absorption. A new generalized form of Sievert's law is derived and validated with experimental data, parametrizing the equation for different metals. The role of microstructural trapping sites in parameter identification is discussed, and the parametrized equation is applied to calculate stress-enhanced hydrogen solubility in practical engineering scenarios.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Engineering, Manufacturing
Benjamin Meier, Norica Godja, Fernando Warchomicka, Carlos Belei, Sandra Schaefer, Andreas Schindel, Gregor Palcynski, Reinhard Kaindl, Wolfgang Waldhauser, Christof Sommitsch
Summary: This study provides an overview of the effects of process parameters, print orientation, and post-process treatments on the microstructure and properties of Ti6AlV4 processed by laser powder bed fusion. Parameter optimization and heat treatments can improve the surface roughness and reduce strength anisotropy. Electrochemical polishing can further decrease the surface roughness and increase fracture necking isotropy.
JOURNAL OF MANUFACTURING AND MATERIALS PROCESSING
(2022)
