Article
Materials Science, Multidisciplinary
Xinyue Chen, Xinliang Xie, Hao Wu, Xia Ji, Haopeng Shen, Muhan Xue, He Wu, Qi Chao, Guohua Fan, Qing Liu
Summary: This work presents a strategy for in-situ controlling the magnitude and distribution of residual stress in laser powder bed fusion (LPBF) process. The residual stress was manipulated by regulating layer thickness, preheating temperature, and scanning strategies. The findings provide an effective approach for reducing stress during LPBF, which is critical for the fabrication of large-scale or complicated-shape metal components.
MATERIALS CHARACTERIZATION
(2023)
Article
Engineering, Manufacturing
Ranxi Duan, Sheng Li, Biao Cai, Weiwei Zhu, Fuzeng Ren, Moataz M. Attallah
Summary: In this study, a metastable beta Ti-12Mo-6Zr-2Fe (TMZF) alloy with highly dense structure was successfully fabricated using laser powder bed fusion from low-cost elemental powders. The alloy exhibited low elastic modulus and high strength, but with a certain level of brittleness. After solution heat treatment, the alloy showed lower elastic modulus and maintained high strength. The TMZF alloy demonstrates comparable strength to Ti-6Al-4V alloy, but with much lower elastic modulus, making it a potential candidate for certain implant applications.
ADDITIVE MANUFACTURING
(2021)
Article
Engineering, Multidisciplinary
Ranxi Duan, Sheng Li, Biao Cai, Zhi Tao, Weiwei Zhu, Fuzeng Ren, Moataz M. Attallah
Summary: This study optimized the laser powder bed fusion parameters to fabricate a highly dense metastable beta Ti-12wt% Mo alloy, and found that different laser area energy densities had significant effects on microstructure and mechanical properties. By adjusting the laser parameters, a Ti-Mo functional gradient composite with high compressive yield strength and improved strain hardening capacity was successfully fabricated.
COMPOSITES PART B-ENGINEERING
(2021)
Article
Engineering, Manufacturing
M. Roscher, S. Balachandran, D. Mayweg, E. Jaegle
Summary: This study examines the feasibility of using Ti as the main strengthening element in the design of precipitation-strengthened alloys, demonstrating the significant role of L1(2)-Al3X-forming elements in enhancing the strength and reducing the susceptibility of aluminium alloys to solidification cracking. By incorporating Si and Ni into the alloy processing, Al-Ti alloys were fabricated, with the Al-2.51Ti-0.7Si alloy reaching a peak hardness of 97HV during heat treatment. This suggests that Si plays a crucial role in enhancing the precipitation process and diffusion of Ti in these alloys.
ADDITIVE MANUFACTURING
(2021)
Article
Engineering, Manufacturing
S. A. Mantri, M. S. K. K. Y. Nartu, S. Dasari, A. Sharma, P. Agrawal, R. Salloom, F. Sun, E. Ivanov, K. Cho, B. McWilliams, S. G. Srinivasan, N. B. Dahotre, F. Prima, R. Banerjee
Summary: The study found that the LPBF processed Ti-10V-2Fe-3Al alloy lacked ductility and strain hardenability due to the formation of isothermal omega precipitates during fabrication, but after a beta-solution heat treatment, the TRIP/TWIP effects were reactivated, leading to substantial recovery of tensile ductility and very high strain hardening rate. This high strain hardening rate is believed to be a result of rapid strain-induced transformation from beta to alpha during plastic deformation, coupled with hierarchical twinning within the martensite plates.
ADDITIVE MANUFACTURING
(2021)
Article
Engineering, Manufacturing
Aya Takase, Takuya Ishimoto, Ryoya Suganuma, Takayoshi Nakano
Summary: This study systematically investigates the effects of heat source type and process parameters on the surface residual stress and phase stability of an unstable 13-type titanium alloy. The research shows significant differences between the laser and electron beam powder bed fusion methods in terms of residual stress and phase behavior in the alloy.
ADDITIVE MANUFACTURING
(2021)
Article
Engineering, Manufacturing
Ammarueda Issariyapat, Shota Kariya, Kazuki Shitara, Junko Umeda, Katsuyoshi Kondoh
Summary: This study explored the ability of nitrogen to reduce the degree of anisotropy in laser-based powder bed fusion (L-PBF) fabricated Ti materials. It was found that low nitrogen content resulted in anisotropic tensile properties, while high nitrogen content significantly reduced anisotropy and improved strength and ductility.
ADDITIVE MANUFACTURING
(2022)
Article
Chemistry, Physical
Yaojia Ren, Xinyan Liu, Hui Wang, Yang Yang, Ian Baker, Pengfei Wang, Hong Wu
Summary: Good mechanical properties were achieved in laser powder bed fusion-produced titanium by promoting the columnar to equiaxed transition through alloying with copper. Thermal cycling along the build direction led to the segregation of copper and conversion of compressive to tensile residual stress. The friction coefficient, hardness, and wear resistance were similar in different sections of the build, and the wear mechanism was a combination of abrasive and delamination wear.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Engineering, Manufacturing
Zhaowen Geng, Chao Chen, Ruidi Li, Jinru Luo, Kechao Zhou
Summary: This study investigated the effects of using pre-alloyed and blended powders to prepare AlCoCrFeNi2.1 eutectic high-entropy alloys. The alloy built with pre-alloyed powder exhibited cellular structures with poor ductility, while the alloy built with blended powders had lamellar structures with high strength and good ductility.
ADDITIVE MANUFACTURING
(2022)
Article
Chemistry, Physical
K. Yang, X. Yang, Z. L. Zhang, T. T. Zhu, J. Li, X. S. Xiao, Y. X. Liang, B. Jian, C. Li, S. N. Luo
Summary: The spall damage of Ti-6Al-4V alloy fabricated via laser powder bed fusion (LPBF) was investigated through plate impact in the build direction (BD) and the transverse direction (TD), focusing on its mechanisms and microstructure effects. Comparative analysis was performed on conventionally hot-rolled Ti-6Al-4V alloys processed with annealing and quenching. Results showed that the spall strength and Hugoniot elastic limit (HEL) of LPBF-fabricated samples were higher in the TD loading than in the BD loading. The LPBF-fabricated alloy exhibited a lower HEL but similar spall strength compared to conventionally fabricated alloys. The anisotropy in mechanical properties and damage was attributed to columnar prior beta grains, morphological, and crystallographic texture of martensite laths.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Sheng Huang, R. Lakshmi Narayan, Joel Heang Kuan Tan, Swee Leong Sing, Wai Yee Yeong
Summary: This study investigated the influence of laser power, velocity, and profile on the porosity, inclusion content, and microstructural evolution of in-situ alloyed laser powder bed fusion manufactured Ti34Nb. It found that a specific combination of laser profile, power, velocity, and scanning strategy could result in the formation of an ideal microstructure.
Article
Materials Science, Composites
Zezhou Xu, Yunting Guo, Yuting Liu, Pengwei Sha, Jundong Zhang, Ping Liang, Zhenglei Yu, Zhihui Zhang, Luquan Ren
Summary: This study investigated the application of rare earth element CeO2 in LPBF-NiTi alloy. SEM, EDS, EBSD, and TEM were used to characterize the microstructure and composition of the samples, and the anti-tribocorrosion resistance was studied in 3.5 wt% NaCl solution. The results showed that the addition of 0.03% CeO2 weakened the strong texture of LPBF-NiTi alloy and refined the grain. A new NiCe phase and lattice distortion were observed in TEM. Furthermore, the addition of 0.03% CeO2 significantly improved the anti-tribocorrosion resistance of LPBF-NiTi alloy in 3.5% NaCl solution.
COMPOSITES COMMUNICATIONS
(2023)
Article
Biochemistry & Molecular Biology
Agnieszka Chmielewska, Anna Dobkowska, Ewa Kijenska-Gawronska, Michal Jakubczak, Agnieszka Krawczynska, Emilia Choinska, Agnieszka Jastrzebska, David Dean, Bartlomiej Wysocki, Wojciech Swieszkowski
Summary: This study compared the corrosive and biological properties of NiTi alloy parts fabricated using pre-alloyed NiTi powder and in situ alloyed pure Ni and Ti powders. The in situ alloyed NiTi exhibited slightly lower corrosion resistance in phosphate buffered saline and a weaker passive layer compared to pre-alloyed NiTi. However, both types showed comparable cytotoxicity and biological properties. In conclusion, nitinol sintered using in situ alloyed pure Ni and Ti shows potential for biomedical applications.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Materials Science, Multidisciplinary
Joachim Gussone, Marcus Willi Rackel, Silvana Tumminello, Pere Barriobero-Vila, Frederic Kreps, Klemens Kelm, Andreas Stark, Norbert Schell, Florian Pyczak, Jan Haubrich, Guillermo Requena
Summary: We studied the microstructure formation of a Ti-22Al-25Nb alloy during laser powder bed fusion (LPBF) at low and high pre-heating temperatures. Low-temperature LPBF resulted in a metastable weakly ordered β phase with a pronounced 100 texture in the build direction and nanosized segregations within elongated grains. High-temperature LPBF showed a Widmanstätten microstructure with lenticular O phase precipitates within the β matrix. The microstructure formation can be explained by the precipitation of O phase from supersaturated β rather than solid-state phase transformations expected under thermodynamic equilibrium conditions. However, the process energy density plays a relevant role, and precipitation from metastable β alone cannot explain the observed microstructures.
MATERIALS & DESIGN
(2023)
Article
Chemistry, Physical
M. H. Mosallanejad, B. Niroumand, A. Aversa, D. Manfredi, A. Saboori
Summary: This study investigates the correlations between volumetric energy density and structural features of in-situ Ti-5 wt.% Cu alloys produced by Laser powder bed fusion method, highlighting the importance of selecting constituent sizes based on thermophysical properties. Results show that with increasing volumetric energy density, crystallite size and lattice distortion of the a phase in the alloy increase, leading to improved isotropy of the microstructure at higher VEDs.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Biomedical
A. M. Vilardell, A. Takezawa, A. du Plessis, N. Takata, P. Krakhmalev, M. Kobashi, M. Albu, G. Kothleitner, I Yadroitsava, I Yadroitsev
Summary: This study reports the first incorporation of copper directly into cellular lattice structures for implant applications through in-situ alloying. The new alloy, combining Ti6Al4V(ELI) and pure Cu powders, produced lattice structures with improved antibacterial properties. Microstructural and mechanical characterizations revealed that in-situ alloying with copper led to enhanced hardness and strength, showing promising potential for direct manufacturing of antibacterial implants.
JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
A. M. Vilardell, S. B. Hosseini, M. Asberg, A. Dahl-Jendelin, P. Krakhmalev, C. Oikonomou, S. Hatami
Summary: This research examined the performance of a novel hot-work tool steel for aluminum die casting applications manufactured by laser powder bed fusion, finding that appropriate heat treatment and hot isostatic pressing significantly improved material hardness and toughness, while nitriding treatment may reduce impact toughness.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Manufacturing
Mfanufikile Shange, Ina Yadroitsava, Anton du Plessis, Igor Yadroitsev
Summary: The study investigated the surface roughness and near-surface porosity resulting from unsupported overhangs at varying inclination angles and orientations during manufacturing Ti6Al4V parts with a high-speed and high-power LPBF system. Results showed that surface roughness and porosity vary as a function of inclination angle.
3D PRINTING AND ADDITIVE MANUFACTURING
(2022)
Article
Engineering, Mechanical
A. Mussa, P. Krakhmalev, J. Bergstrom
Summary: This study investigated the sliding wear resistance of two austempered ductile irons (ADI1 and ADI2) commonly used in mining and construction equipment. The results showed that ADI1 with a higher volume of carbon-rich austenite exhibited better wear resistance at high normal loads, while ADI2 with higher silicon content showed lower wear resistance due to cracking of the proeutectoid ferrite.
Article
Materials Science, Multidisciplinary
Anna Martin Vilardell, Ina Yadroitsava, Winston Kagisho Curtis Wolf, Anton Du Plessis, Muofhe Tshibalanganda, Dean-Paul Kouprianoff, Natalia Garcia-Giralt, Makoto Kobashi, Igor Yadroitsev
Summary: Additive manufacturing (AM) can enhance the functionality and design customization of medical applications. This study focused on the manufacturing and characterization of a polyamide-copper composite, which showed promising properties for medical applications.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Engineering, Biomedical
Anna Martin Vilardell, Vanesa Cantillo Alzamora, Luana Vittoria Bauso, Cristina Madrid, Pavel Krakhmalev, Mihaela Albu, Ina Yadroitsava, Igor Yadroitsev, Natalia Garcia-Giralt
Summary: In situ-alloyed Ti6Al4V(ELI)-3at.%Cu was successfully manufactured by laser powder bed fusion. Stress relieving and annealing treatments resulted in microstructural changes, with an increase in β phase and CuTi2 intermetallic precipitates. The increase in Cu ions release from the β phase led to antibacterial behavior and inhibited biofilm formation.
JOURNAL OF FUNCTIONAL BIOMATERIALS
(2023)
Article
Chemistry, Physical
A. M. Vilardell, L. Pelcastre, D. Nikas, P. Krakhmalev, M. Kato, N. Takata, M. Kobashi
Summary: Prealloyed Fe3Al with high density, good surface quality, and suitable mechanical properties was successfully manufactured using laser powder bed fusion. The presence of minor variations in aluminum content along the melt pool and the development of a weak texture along the building direction were observed in the microstructure. The mechanical properties were found to be temperature-dependent, with a significant loss in strength at higher temperatures due to plastic deformation and tribochemical wear.
Review
Engineering, Industrial
Oliver Hentschel, Pavel Krakhmalev, Gunnel Fredriksson, Jon Olsen, Aydin Selte, Michael Schmidt
Summary: This study investigates the manufacturing of experimental maraging tool steel using Directed Energy Deposition using laser and metallic powder. The build microstructure is characterized using advanced electron microscopy, and the hardness properties are evaluated. The results show high printability and low porosity in the final builds, with a gradient in microstructure and properties along the height. The top layers exhibit a structure of martensite with precipitates formed during solidification, while the inner regions have a higher hardness due to in-situ heat treatment. The formation of quasicrystalline nano-sized R'-phase precipitates in the inner regions is discussed as a reason for the higher hardness.
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Faezeh Javadzadeh Kalahroudi, Mohamed Sadek, Pavel Krakhmalev, Tomas Berglund, Jens Bergstrom, Mikael Grehk
Summary: This paper investigates the microstructure and fatigue behavior of PM-HIPed Inconel 625. The samples show good tensile properties with high elongation despite the presence of carbonitrides. The fatigue strength of pickled samples is found to be 6% lower with higher standard deviation compared to machined samples, indicating different fatigue failure mechanisms.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Dominic Bartels, Mikael Fallqvist, Miriam Heise, Johannes Vetter, Michael Schmidt, Pavel Krakhmalev
Summary: Laser-based directed energy deposition of metals allows for in-situ modification of alloying composition, resulting in functional materials with tailored properties. The addition of carbon and tungsten carbide (WC) improved hardness and wear resistance. Scratches showed an anisotropic abrasive wear resistance, influenced by microstructural differences between weld tracks.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Yulia O. Kuzminova, Denis G. Firsov, Anastasia A. Shibalova, Egor A. Kudryavtsev, Pavel Krakhmalev, Olga G. Klimova-Korsmik, Igor V. Shishkovsky, Stanislav A. Evlashin
Summary: High-entropy Alloys (HEAs) are promising materials for harsh conditions and additive manufacturing (AM) can be used for adjusting their composition. In this study, CrFeCoNi(Al,Ti) HEAs were printed by powder bed fusion (PBF) using a blend of three powders. The investigation revealed chemical inhomogeneity and phase formations in the printed alloys, which can be influenced by post-treatment processes such as high-temperature annealing.
Proceedings Paper
Computer Science, Software Engineering
Yunpeng Ma, Khalil Younis, Bestoun S. Ahmed, Andreas Kassler, Pavel Krakhmalev, Andreas Thore, Hans Lindback
Summary: Digital twins (DT) of industrial processes are increasingly important, aiming to digitally represent and optimize physical processes. This paper presents an automated and systematic test architecture for DT, correlating DT states with real-time sensor data to accelerate the testing process and improve reliability.
2023 IEEE INTERNATIONAL CONFERENCE ON SOFTWARE TESTING, VERIFICATION AND VALIDATION WORKSHOPS, ICSTW
(2023)
Article
Engineering, Mechanical
D. Kouprianoff, I Yadroitsava, A. du Plessis, N. Luwes, I Yadroitsev
Summary: This paper demonstrates an approach to using acoustic emission for online monitoring of the L-PBF process. Analysis of acoustic signals allows for identification of characteristic amplitudes and frequencies, supporting its use as a complementary method for real-time defect detection.
FRONTIERS IN MECHANICAL ENGINEERING-SWITZERLAND
(2021)
Article
Metallurgy & Metallurgical Engineering
N. V. Kazantseva, P. V. Krakhmalev, I. A. Yadroitsava, I. A. Yadroitsev
Summary: The study examined the features of 3D printing, focusing on laser melting of metal powders. It reviewed the impact of laser operation mode on the structure, residual stresses, and properties of manufactured metals, and proposed a method for choosing process parameters using single tracks as universal for all types of metal laser 3D printers. Additionally, it presented the structural characteristics and medical requirements for biocompatible materials, specifically discussing the biocompatible Ti-6Al-4V alloy manufactured by selective laser melting.
PHYSICS OF METALS AND METALLOGRAPHY
(2021)
