Article
Nanoscience & Nanotechnology
A. Fedoseeva, E. Tkachev, R. Kaibyshev
Summary: The creep behavior of 9% Cr martensitic steels with different W, N, and B contents was studied at 650 degrees C. The results showed a breakdown in creep strength and a change in apparent stress exponent at applied stresses ranging from 140 to 120 MPa. The threshold stresses, estimated by extrapolation, decreased at the transition from high stress to low stress regions. The sources of these threshold stresses were believed to be dislocations, carbides, and phase particles.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
Kumar Sourabh, J. B. Singh, K. V. Ravikanth, A. Verma
Summary: This study reports the internal nitridation of alloy 690 during creep deformation at 1100°C. Creep tests at various stresses showed normal creep response at higher stresses and oscillatory creep at lower stresses. Nitride precipitates were observed near cracks, caused by the internal nitridation of freshly exposed crack surfaces. Precipitation of nitride particles had little effect on creep life of the alloy.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Chemistry, Physical
Lenka Kuncicka, Michal Jambor, Adam Weiser, Jiri Dvorak
Summary: This study focuses on the detailed characterization of the structure and plastic flow of Cu-Zn-Pb brass fittings. The cracking was most likely induced by differences in chemical composition, with local changes in the crack location and an increase in microhardness contributing to local brittleness.
Article
Materials Science, Multidisciplinary
Olli Nousiainen, Jaakko Hannula, Sami Saukko, Antti Kaijalainen, Jukka Komi
Summary: The precipitation behavior of nanosized carbides in low-alloy Ti-Mo-V-Nb and Ti-Mo-V- steels was investigated during isothermal dwell at different temperatures. The formation and orientation of interphase precipitates (IP) in the ferrite matrix depended on steel chemistry, temperature, and dwelling time. Finely dispersed interphase precipitated V(Mo)C carbides formed rows with increased spacing and size during isothermal dwell, while spherical V(Mo)C carbides formed within the supersaturated ferrite matrix. For Ti-Mo-V steel, interphase precipitated Ti (Mo,V)C carbides only formed at the highest dwell temperature of 680 degrees C.
MATERIALS CHARACTERIZATION
(2023)
Article
Chemistry, Physical
Xu Liu, Lin Song, Andreas Stark, Daria Lazurenko, Florian Pyczak, Tiebang Zhang
Summary: The study investigates the precipitation behavior of the omega(o) phase and creep properties of a Ti-45Al-9Nb-0.5B alloy at intermediate temperatures. It shows that the imposed stress contributes to the nucleation and growth of the omega(o) phase, which can reduce the creep resistance of the material. Additionally, dynamic recrystallization is identified as a primary cause of microstructural degradation.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Nanoscience & Nanotechnology
Yawei Li, Li Wang, Yufeng He, Wei Zheng, Langhong Lou, Jian Zhang
Summary: The study found that as the temperature increases, the spacing of dislocation networks in the gamma/gamma' interface decreases, while the minimum creep rate increases non-linearly. This is due to the enhanced dislocation-climb in the interface and gamma'-cutting by a <010> superdislocations.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
Tian-Xing Yang, Zhan-Xing Li, Chang-Jun Zhou, Yi-Chun Xu, Peng Dou
Summary: FeCrAl oxide dispersion strengthened (ODS) steel is a promising cladding material for Generation IV nuclear reactors due to its superior properties. The morphologies, crystal structures, and metal/oxide interface structures of two FeCrAl ODS steels were studied. The dispersion morphology of oxides in the 3.7Al-0.1Ti-0.6Zr ODS steel was found to be better than that of the 3.3Al-0.5Zr ODS steel. The proportions of different oxides in the two ODS steels were characterized. The mechanisms of oxide formation, polymorphic transition, and strengthening in the ODS steels were discussed.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Yan Liu, Jinshan Li, Bin Tang, Lin Song, William Yi Wang, Dong Liu, Rui Yang, Hongchao Kou
Summary: The decomposition mechanism of (alpha(2) /gamma) lamellae was investigated using transmission electron microscopy (TEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) techniques. The results revealed the facilitated alpha(2)->ss phase transformation and the formation of ellipsoidal omega(o) particles. The mechanism of the lath-shaped omega(o) phase was attributed to both element segregation and strain accommodation caused by the ss o precipitate in alpha(2) lamellae. These findings provide insights into the decomposition mechanism of (alpha(2)/gamma) lamellae and have implications for controlling microstructures and improving the performance of ss-solidified gamma-TiAl alloys.
Article
Nanoscience & Nanotechnology
L. Heep, D. Burger, C. Bonnekoh, P. Wollgramm, A. Dlouhy, G. Eggeler
Summary: The low temperature high stress tensile creep behavior of the superalloy single crystal ERBO-1 was investigated, with comparisons made between loading directions of [001] and deviations towards [111] and [011]. The study found that creep rates are influenced by the loading directions, and faster creep rates are observed when dislocations from two octahedral systems experience similar driving forces.
SCRIPTA MATERIALIA
(2022)
Article
Chemistry, Physical
Jin-Hu Dou, Maxx Q. Arguilla, Yi Luo, Jian Li, Weizhe Zhang, Lei Sun, Jenna L. Mancuso, Luming Yang, Tianyang Chen, Lucas R. Parent, Grigorii Skorupskii, Nicole J. Libretto, Chenyue Sun, Min Chieh Yang, Phat Vinh Dip, Edward J. Brignole, Jeffrey T. Miller, Jing Kong, Christopher H. Hendon, Junliang Sun, Mircea Dinca
Summary: Researchers have successfully grown single crystals of 2D metal-organic frameworks up to 200 µm in size by balancing in-plane and out-of-plane interactions, revealing anisotropic transport and a clear correlation between conductivity and the nature of the metal cation in the sheets.
Article
Materials Science, Multidisciplinary
Yu Tian, Hao Yu, Tao Zhou, Kun Wang, Zimeng Zhu
Summary: This study reveals the precipitation behavior and morphological characteristics of MX precipitates in deformed Ti-V-Nb multi-microalloyed steels, introducing the L parameter model for evaluating the shape of precipitates. The evolution rules of precipitate morphology provide insights for developing high-performance microalloyed steels.
MATERIALS CHARACTERIZATION
(2022)
Article
Chemistry, Multidisciplinary
Joel Ribis, Isabelle Mouton, Cedric Baumier, Aurelie Gentils, Marie Loyer-Prost, Laurence Luneville, David Simeone
Summary: Oxide dispersion-strengthened materials are reinforced by (Y, Ti, O) nano-oxide dispersion and exhibit different behaviors of nano-oxides at different temperatures. Maintaining the nano-oxide dispersion under irradiation is crucial for preserving the excellent creep properties of the alloy in a nuclear power plant.
Article
Materials Science, Multidisciplinary
Dongwon Lee, Yoon-Uk Heo, Jae Sang Lee, Won-Tae Cho, Unhae Lee, Myeong-Hun Kang, Chang Hee Yim
Summary: The role of AlN on the internal oxidation behavior in Al-containing high Mn steels was investigated. The results confirmed that increased Al contents led to accelerated internal oxidation. Sequential formation of internal oxidation and AlN + gamma-matrix layers was observed in the steel after heat treatment in air.
MATERIALS CHARACTERIZATION
(2022)
Article
Materials Science, Multidisciplinary
Vassili A. Vorontsov, Thomas P. McAuliffe, Mark C. Hardy, David Dye, Ioannis Bantounas
Summary: The tensile creep performance of a polycrystalline Co/Ni-base superalloy with a multimodal gamma' distribution was studied at 800 degrees C and 300 MPa. The rupture life of the alloy was comparable to that of RR1000 tested under similar conditions. Microstructural examination revealed the presence of continuous gamma' precipitates and M23C6 carbides along the grain boundaries, as well as the coarsening of the secondary gamma' precipitates. Long planar deformation bands, identified as microtwins, were observed along with the depletion of gamma' stabilising elements. The mechanism for precipitate dissolution was suggested to be the Kolbe reordering mechanism.
Article
Nanoscience & Nanotechnology
A. Bezold, L. Amon, N. Karpstein, E. Spiecker, M. Goken, S. Neumeier
Summary: Stacking fault shearing is commonly observed in Co-base and CoNi-base superalloys in the intermediate temperature regime, and the recovery processes after aging and creep experiments are significant. Superlattice stacking faults recover more quickly than intrinsic ones above 950℃. Moreover, the significance of stacking fault shearing in the high temperature creep regime could be higher than traditionally indicated due to recovery processes.
SCRIPTA MATERIALIA
(2023)
Article
Chemistry, Physical
Ernst Plesiutschnig, Mihaela Albu, David Canelo-Yubero, Vsevolod Razumovskiy, Andreas Stark, Norbert Schell, Gerald Kothleitner, Coline Beal, Christof Sommitsch, Ferdinand Hofer
Summary: The quality of heat treatment plays a crucial role in determining the unique properties of precipitation hardened and tempered martensitic-ferritic steels used in various industries. Atomic-scale studies and thermodynamic calculations help in understanding how dislocations facilitate cloud formation around carbides and explain the stability of these clouds.
Article
Nanoscience & Nanotechnology
S. Zeisl, A. Lassnig, A. Hohenwarter, F. Mendez-Martin
Summary: The influence of severe plastic deformation on the hardness and precipitation behavior of a Co-free maraging steel was investigated in this study. It was found that severe plastic deformation transformed the microstructure, delayed austenite reversion, and accelerated and influenced the precipitation reaction, thus affecting the characteristics of intermetallic phases.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Metallurgy & Metallurgical Engineering
Michael Rhode, Tim Richter, Tobias Mente, Peter Mayr, Alexander Nitsche
Summary: Martensitic 9% Cr steels like P91 and P92 exhibit susceptibility to delayed hydrogen assisted cracking depending on microstructure. Effective hydrogen diffusion coefficients are used to evaluate possible time delay. Different methods were used to calculate diffusion coefficients, showing that sample thickness must be considered as it impacts the results.
WELDING IN THE WORLD
(2022)
Article
Chemistry, Physical
Mihaela Albu, Bernd Panzirsch, Hartmuth Schroettner, Stefan Mitsche, Klaus Reichmann, Maria Cecilia Poletti, Gerald Kothleitner
Summary: The research systematically investigated the relationship between the properties of powder grains and the microstructure of printed parts of X5CrNiCuNb17-4 maraging steel using powder and selective laser melting (SLM) techniques. It was proven that oxide reactions can be transformed into advantages, showing the stability of oxide particles and the potential for oxide-dispersive strengthening.
Article
Materials Science, Multidisciplinary
Josef Domitner, Zahra Silvayeh, Ricardo Henrique Buzolin, Sabine Krisam, Klaus Achterhold, Erwin Povoden-Karadeniz, Christof Sommitsch, Peter Mayr
Summary: This study provides detailed experimental characterization of a laser-clad metal matrix composite (MMC) consisting of hard tungsten carbide particles embedded in a comparatively soft nickel-based matrix. The relationship between the microstructure of the as-deposited reinforcing particles and their hardness is investigated. The dissolution of carbides caused by the high process temperature of laser metal deposition (LMD) is observed, leading to the formation of secondary phases at the matrix/particle interfaces and a gradual decrease in local hardness.
ADVANCED ENGINEERING MATERIALS
(2022)
Article
Crystallography
Sandi Zist, Matej Steinacher, Tonica Boncina, Mihaela Albu, Jaka Burja, Maja Voncina, Franc Zupanic
Summary: The effects of 0.2 wt.% and 1 wt.% scandium (Sc) additions on the microstructure of aluminium alloy AA 6086 were investigated. It was found that the addition of Sc significantly reduced the grain size and induced the appearance of Sc-rich phases. Homogenisation resulted in the dissolution of most phases and the formation of different types of dispersoids. The addition of 0.2% Sc did not considerably affect the strengthening of AA 6086.
Article
Automation & Control Systems
Natan Nudelis, Peter Mayr
Summary: Due to high production costs and limited quality reproducibility, the full potential of laser powder bed fusion (LPBF) has not been fully utilized. This study investigates the correlation between pores and LPBF process parameters in AlSi10Mg components using computed tomography (CT). The findings suggest that the formation of pores can be controlled by adjusting the modified volume energy density and powder preparation scan strategies.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2022)
Article
Metallurgy & Metallurgical Engineering
Michael Rhode, Jonathan Nietzke, Tim Richter, Tobias Mente, Peter Mayr, Alexander Nitsche
Summary: This study investigates the microstructure and heat treatment effects on the mechanical properties of P92 base material and P91 multi-layer weld metal, as well as establishing a fracture criterion dependent on hydrogen and microstructure. All investigated microstructures show a degradation of mechanical properties compared to hydrogen-free samples, with the as-welded P91 weld metal exhibiting the highest degree of degradation in the presence of hydrogen. The P91 PWHT weld metal and P92 base material exhibit comparable properties.
WELDING IN THE WORLD
(2023)
Article
Materials Science, Multidisciplinary
Peter Panjan, Peter Gselman, Matjaz Panjan, Tonica Boncina, Aljaz Drnovsek, Mihaela Albu, Miha Cekada, Franc Zupanic
Summary: The microstructure and surface topography of the TiAlN/CrN nanolayer coating were systematically analyzed in this study. The effects of substrate rotation modes, substrate material, and ion etching methods on the coating were investigated, with special attention given to the influence of non-metallic inclusions. The results indicate that substrate rotation modes significantly influence the microstructure, surface topography, and periodicity of the coating layer.
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
Engineering, Civil
Lukasz Rakoczy, Malgorzata Grudzien-Rakoczy, Bogdan Rutkowski, Rafal Cygan, Fabian Hanning, Grzegorz Cios, Stefan Habisch, Joel Andersson, Peter Mayr, Anna Zielinska-Lipiec
Summary: This study investigates the influence of microstructural constituents on liquation crack formation in the cast Ni-based superalloy, Rene 108. It is found that the base material has a complex microstructure, including gamma matrix, gamma' precipitates, MC and M23C6 carbides, and M5B3 borides. The constitutional liquation in the alloy leads to a significant reduction in strength and ductility, resulting in low weldability. In the heat-affected zone, mainly gamma' precipitates undergo constitutional liquation, forming a thin non-equilibrium liquid film along high-angle grain boundaries, which initiates and propagates cracks during cooling.
ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING
(2023)
Article
Chemistry, Physical
Franc Zupanic, Sandi Zist, Mihaela Albu, Ilse Letofsky-Papst, Jaka Burja, Maja Voncina, Tonica Boncina
Summary: This study investigates the effects of Sc and Y on the formation of dispersoids in the aluminum alloy AA 6086, particularly the L1(2)-type ones, to increase its high-temperature strength. Various techniques such as LM, SEM, TEM, EDS, XRD, DSC, and dilatometry were used to understand the mechanisms and kinetics of dispersoid formation during isothermal treatments. Sc and Y promote the formation of L1(2) dispersoids during heating, homogenization, and isothermal heat treatments, resulting in the highest hardness when heat-treated in the as-cast state between 350°C and 450°C (via T5 temper).
Article
Materials Science, Multidisciplinary
Natan Nudelis, Peter Mayr
Summary: This research focuses on the effect of hot isostatic pressing (HIP) on the pore characteristics of AlSi10Mg components. The study reveals that longer treatment times and higher pressure and temperature settings accelerate the pore transformation, with irregularly shaped and large pores closing faster than spherically shaped and smaller ones. Regardless of the initial pore type, all pores tend to transform towards irregular shapes and smaller diameters during HIP.
JOURNAL OF MATERIALS SCIENCE
(2023)
Proceedings Paper
Computer Science, Artificial Intelligence
Majid Shirazi, Markus Schmitz, Simon Janssen, Anabelle Thies, Georgij Safronov, Amr Rizk, Peter Mayr, Philipp Engelhardt
Summary: Sparse and imbalanced data pose challenges for deep learning quality inspection systems, with synthetic image generation through Generative Adversarial Networks offering a potential solution. However, introducing synthetic images may have adverse effects on detection performance and system robustness, requiring further research to improve object detection systems in quality inspection.
20TH IEEE INTERNATIONAL CONFERENCE ON MACHINE LEARNING AND APPLICATIONS (ICMLA 2021)
(2021)
Article
Environmental Sciences
Tetyana Milojevic, Mihaela Albu, Denise Kolbl, Gerald Kothleitner, Robert Bruner, Matthew L. Morgan
Summary: Multiple lines of evidence suggest an active hydrogeological history of Mars and environments suitable for chemolithoautotrophy. Future missions aim to search for signs of ancient life on Mars. Laboratory-scaled research on Noachian Martian breccia revealed microbial-assisted biotransformation, providing insight into the distribution of meteorite inorganic constituents in microbial cells.
COMMUNICATIONS EARTH & ENVIRONMENT
(2021)
