Article
Materials Science, Multidisciplinary
Yichao Wang, Xiangyi Xue, Hongchao Kou, Yonghao Yu, Mengyu Jia, Jinshan Li
Summary: The impact of interfacial beta(0) phase on the creep properties of TNM alloy was investigated. It was found that the fine-dispersed beta(0) phase effectively strengthened the creep resistance and maintained the integrity of the lamellar structure.
MATERIALS RESEARCH LETTERS
(2022)
Article
Materials Science, Multidisciplinary
A. J. Egan, F. Xue, Y. Rao, G. Sparks, E. Marquis, M. Ghazisaeidi, S. Tin, M. J. Mills
Summary: This study investigates the effect of Nb content on local phase transformation strengthening during high temperature creep in two similar polycrystalline alloys. The results show that the alloy with higher Nb content exhibits superior creep strength. Characterization of the deformation microstructures and density functional theory calculations reveal that a novel local phase transformation along microtwin interfaces plays a key role in enhancing the creep strength.
Review
Chemistry, Multidisciplinary
Jinmei Chen, Xiaosong Jiang, Hongliang Sun, Zhenyi Shao, Yongjian Fang, Rui Shu
Summary: High-entropy alloys (HEAs) have gained attention for their excellent performance in aerospace, ultrahigh temperature, high-performance, and biomimetic materials. Current research on HEAs focuses on microstructure and mechanical properties, with the emergence of medium-entropy alloys, metastable HEAs, dual-phase HEAs, and multiphase HEAs adding complexity to the system.
NANOTECHNOLOGY REVIEWS
(2021)
Article
Materials Science, Multidisciplinary
Zhufeng He, Nan Jia, Hongwei Wang, Haile Yan, Yongfeng Shen
Summary: High-entropy alloys (HEAs) with nitrogen-doped FeMnCoCr composition show excellent mechanical properties at low temperatures, achieving high strength and ductility without compromise. The microstructural evolution, including athermal martensitic transformation and mechanical twinning activation, along with the dynamic Hall-Petch effect and transformation induced plasticity, contribute to the ultrahigh tensile strength and ductility of the alloys. The design strategy of adjusting stacking fault energy in interstitial metastable HEAs paves the way for developing high-performance and cost-effective alloys for cryogenic applications.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
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
Materials Science, Multidisciplinary
Delin Zhang, Ananya Renuka Balakrishna
Summary: During the reversible insertion of ions in intercalation materials, lattice transformations occur, leading to structural decay and limited reversible cycling. This article draws on insights from shape-memory alloys and develops a theoretical framework to predict structural transformations in intercalation compounds. By applying this approach to screen structural databases, candidate compounds that satisfy crystallographic design rules and can form shape-memory-like microstructures are identified. Results show a direct correlation between structural transformations, microstructures, and increased capacity retention in intercalation materials, suggesting crystallographic designing as a novel route to discover non-decaying compounds.
Article
Nanoscience & Nanotechnology
Junko Umeda, Takayuki Tanaka, Takuma Teramae, Shota Kariya, Junji Fujita, Hiroshi Nishikawa, Yoji Shibutani, Jianghua Shen, Katsuyoshi Kondoh
Summary: In this study, Ti-Fe alloys were fabricated using Fe as a beta-phase stabilizer via powder metallurgy. The addition of Fe resulted in increased beta-Ti volume fraction and refined alpha-Ti grains, leading to significant improvements in tensile strength and ductility. The dominant strengthening factors for these alloys were alpha-Ti grain refinement and beta-Ti hard phase dispersion, with 50% of the yield stress increase attributable to the latter mechanism in the case of 4 wt% Fe addition.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Manufacturing
Zhenyu Chen, Annan Chen, Qingbo Jia, Zhixin Xia, Ruidi Li, Chuanyang Wang, Jie Pan, Yusheng Shi
Summary: This study investigates the microstructures, strengthening mechanisms, and deformation behaviors of a novel N-doped Co-28Cr-6Mo alloy fabricated by laser powder bed fusion (LPBF). The LPBF fabricated CCMN alloy shows superior yield strength and elongation to fracture, as the grain boundaries, dislocations, Cr2N precipitates, and stacking faults are identified as the main strengthening contributors. Furthermore, the HCP phase and Lomer-Cottrell locks enhance the strain hardening rate, while the formed Cr2N nanoprecipitates suppress strain localization and premature failure, contributing to the high ductility of the alloy.
VIRTUAL AND PHYSICAL PROTOTYPING
(2023)
Article
Nanoscience & Nanotechnology
Yijie Bian, Ruicheng Wang, Fan Yang, Puhao Li, Yicheng Song, Jiemin Feng, Wenwang Wu, Ziyong Li, Yang Lu
Summary: In this paper, novel multiphase heterogeneous lattice materials are developed using the precipitation strengthening mechanism in metal metallurgy. By utilizing the hindering effect of second-phase lattice cells on shear band propagation, the mechanical properties of the materials are enhanced. Different from conventional random distribution, second-phase and third-phase cells are continuously distributed along the regular pattern of a larger-scale lattice to form internal hierarchical lattice structures. The results show that the triphase lattices possess balanced mechanical properties and introducing a relatively weak phase can improve stiffness and plateau stress, contrary to the common mixed rule.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Zhen Xu, Zhiwei Lv, Chuan Guo, Yang Zhou, Gan Li, Xiaogang Hu, Xinggang Li, Qiang Zhu
Summary: The steady-state creep mechanisms of a superlattice gamma'-strengthened Co-Al-W-Ta-Ti single crystal superalloy were studied under different temperature and stress conditions. The microstructures of the creep samples varied significantly according to the experimental conditions. Lomer-Cottrell locks and stacking faults interactions dominated the low-temperature and high-stress creep regime, while dislocations cross-slip and dislocation tangles contributed to the main creep resistance at intermediate temperatures and moderate stresses. The interactions of stacking faults and dislocation networks were the strengthening mechanism for the high-temperature and low-stress creep regime. The steady-state creep rate followed a classical power law equation, with a calculated creep activation energy of 378.46 kJ/mol. These findings provide insights into the effects of temperature and stress on steady-state creep mechanisms, and highlight the potential of the gamma'-strengthened Co-Al-W-Ta-Ti single crystal superalloy as a high-temperature structural material.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
Filip Siska, Hynek Hadraba, Ludek Stratil, Stanislava Fintova, Ivo Kubena
Summary: The effect of grain orientation on the mechanical behavior of the 14Cr ODS steel was investigated. The study found that both grain orientations provide similar strengthening up to 600℃, while the orientation parallel to the extrusion direction provides higher strength at temperatures 700-800℃.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Chemistry, Physical
Min-Seok Baek, Abdul Wahid Shah, Young-Kyun Kim, Shae-K. Kim, Bong-Hwan Kim, Kee-Ahn Lee
Summary: This study investigated the microstructures, mechanical properties, tensile deformations, and strengthening mechanisms of Al-Mg alloys with different Mg contents. Higher Mg content resulted in higher fractions of C15 phases and increased yield strengths. The 9Mg alloy exhibited better resistance to serrated flow due to its fine equiaxed grains and higher Mg content and number densities of obstacles. Solid-solution and grain-boundary strengthening contributed to the overall yield strength. The study demonstrated the potential of conventional models to accurately predict the yield strengths of Al-Mg alloys.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Taotao Ruan, Junjie Shen, Bo Li, Zhihang Zhao, Dechang Zhang
Summary: The study analyzed the strengthening mechanism and effect of Fe2Nb and Fe2W Laves phase alloys in a ferritic matrix, indicating that Fe2Nb-type Laves phase may be more suitable as a strengthener in the ferritic matrix compared with Fe2W-type.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Chemistry, Physical
Danni Yang, Yong Liu, Nan Qu, Tianyi Han, Mingqing Liao, Zhonghong Lai, Jingchuan Zhu
Summary: The effect of fabrication methods on microstructures, mechanical properties, and strengthening mechanisms of high-entropy alloys was systematically studied. Different fabrication methods have little effect on the main phase compositions of Fe0.25CrNiAl MEA, but significant impacts on microstructures, mechanical properties, and strengthening mechanisms were observed.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Nanoscience & Nanotechnology
M. R. Gazizov, A. N. Belyakov, R. Holmestad, M. Yu. Gazizova, V. S. Krasnikov, P. A. Bezborodova, R. O. Kaibyshev
Summary: The coarsening behavior of strengthening particles in peak-aged Al-Cu-Mg-Ag alloy during creep at 150 degrees C and 165 degrees C has been studied. It was found that the average thickness and diameter of {111}Al omega plates strongly depend on creep time and less on applied stress levels and plastic strain during creep. The volume fraction of omega particles increased during long-term creep and exceeded the value after peak aging. S-phase and theta'-phase independently nucleate and intergrow to form precipitate complexes. The size of the complex particles is sensitive to the plastic strain level achieved at different applied stresses during creep.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Kathrin Maier, Thomas Kluensner, Philip Pichler, Stefan Marsoner, Werner Ecker, Christoph Czettl, Jonathan Schafer, Reinhold Ebner
Summary: The study aimed to analyze the fatigue failure mechanisms of WC-Co hardmetals under high-temperature cyclic loading conditions, finding that failure occurred earlier at 800 degrees Celsius than at 700 degrees Celsius. It was observed that the stress-strain hysteresis loop parameters were related to the damage evolution state at the microstructure level and the deformation behavior of WC and Co phases with increasing number of load cycles.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Kathrin Maier, Thomas Klunsner, Philip Pichler, Stefan Marsoner, Werner Ecker, Christoph Czettl, Jonathan Schafer, Reinhold Ebner
Summary: This study aimed to experimentally determine limit stresses leading to advancing ratcheting in different grades of WC-Co hardmetals at elevated temperatures. The plastic strain per cycle decreases below the limit stress, with accumulation stopping after a number of cycles. Microstructural influence on ratcheting onset and damage development was investigated.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Lukas Walch, Thomas Kluensner, Martin Krobath, Kathrin Maier, Werner Ecker, Philip Pichler, Christoph Czettl, Reinhold Ebner
Summary: In the metalworking industry, hard-coated WC-Co hardmetal tools are commonly used, but their tool life is limited by pre-existing defects and defects formed during use. This study presents a novel material testing method using a spherical indenter and inclined specimen surfaces to apply multi-axial loads, aiming to understand the kinetics of defect formation and accumulation.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2022)
Article
Engineering, Manufacturing
T. Kaltenbrunner, H. P. Krueckl, G. Schnalzger, T. Klunsner, T. Teppernegg, C. Czettl, W. Ecker
Summary: This study investigates the differences between up-milling and down-milling in terms of thermomechanical loading and tool wear. The results show that up-milling leads to accelerated tool wear compared to down-milling, with the same wear mechanism but a higher wear rate in up-milling. The wear is driven by the growth of fatigue cracks, indicating a mechanical reason for tool wear. Finite element simulations suggest that the specific interaction between thermal and mechanical loading in up-milling is the cause of accelerated tool wear.
JOURNAL OF MANUFACTURING PROCESSES
(2022)
Article
Engineering, Manufacturing
T. Kaltenbrunner, K. Maier, T. Kluensner, H. P. Krueckl, M. Krobath, M. Potz, J. Wosik, O. Binder, T. Teppernegg, C. Czettl, W. Ecker
Summary: The present study investigates the thermal and mechanical tool loading of an indexed cutter with round cutting inserts. The finite element model helps establish the linkage between material damage in laboratory specimens and tool degradation in cutting experiments. The findings suggest that the investigated process conditions are close to the limit of safe tool application.
JOURNAL OF MANUFACTURING PROCESSES
(2022)
Article
Materials Science, Multidisciplinary
Shuang He, Werner Ecker, Oleg E. Peil, Reinhard Pippan, Vsevolod I. Razumovskiy
Summary: This paper investigates the impact of solute atoms dissolved in the Ni matrix on the properties of Ni-based alloys, particularly on the grain boundaries. The changes in partial cohesive energy and grain boundary work of separation are calculated using density functional theory. Machine learning models are then trained using the calculated results and show good predictive capability. The effects of computed solutes on the grain boundary properties in Ni and their impact on the overall resistance of Ni to hydrogen-induced decohesion are analyzed in detail.
Article
Materials Science, Multidisciplinary
Hamdi Elsayed, Andreas Drexler, Fernando Warchomicka, Ines Traxler, Josef Domitner, Matthew Galler, Rudolf Vallant, Christof Sommitsch
Summary: Multiphase ultra-high strength steels with retained austenite have great potential in the automotive industry. Quenching and partitioning heat treatment can achieve a good combination of strength and ductility. However, the susceptibility to hydrogen embrittlement limits the use of Q&P steels. This study investigates the influence of Q&P heat treatment parameters on mechanical properties and hydrogen embrittlement resistivity.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2023)
Article
Chemistry, Physical
Simon Vander Vennet, Silvia Leitner, Vsevolod Razumovskiy, Werner Ecker, Tom Depover, Kim Verbeken
Summary: This study investigates the effect of a constant load on hydrogen diffusion through a Q&P steel containing metastable retained austenite. The results show that hydrogen diffusion is delayed under all stressed conditions, even at stresses in the elastic regime, with the delay increasing with the applied load. Thermal desorption spectroscopy reveals the presence of a high temperature peak in the samples tested under load, indicating hydrogen effusion and release due to the transformation of retained austenite.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Materials Science, Multidisciplinary
Pichler Philip, Klunsner Thomas, Marsoner Stefan, Krobath Martin, Knabl Wolfram, Schatte Juergen, Bienert Christian, Ecker Werner
Summary: The aim of this study was to investigate the time-dependent visco-plastic behavior of the MHC alloy under stress-relieved condition. Cyclic strain-controlled low cycle fatigue experiments were conducted at different temperatures. The results showed the softening ability of the MHC alloy during cyclic loading, especially at high temperatures. The strain rate sensitivity of the stress response and the stress relaxation behavior were also examined.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Fabian Konstantiniuk, Martin Krobath, Werner Ecker, Michael Tkadletz, Christoph Czettl, Nina Schalk
Summary: This study investigates the influence of Co-enriched surface zone and its thickness on the microstructure and mechanical properties of TiN/TiC0.6N0.4/alpha-Al2O3 coatings. The results show that the hardness and Young's modulus of the coatings are hardly affected by the Co-enriched surface zone and its thickness, but the zones with higher Co content in the substrate exhibit lower hardness and Young's modulus. Additionally, the Co-enriched surface zone and its thickness have an effect on the thermal crack networks and adhesion of the coatings.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2023)
Article
Engineering, Multidisciplinary
Claus O. W. Trost, Stanislav Zak, Katharina Ruderes, Rene Hammer, Jordis Rosc, Thomas Krivec, Norbert Schell, Hans-Peter Gaenser, Anton Hohenwarter, Megan J. Cordill
Summary: This paper presents a method for low cycle fatigue testing of metal foils in multifunctional composites, providing detailed information about sample design, fatigue testing, and data extraction. The fatigue failure of copper and Pre-Preg is analyzed using scanning electron microscopy and computed tomography. Numerical models are used to calculate the strains in the copper foils within the composite, allowing correlation to the observed fatigue life.
COMPOSITES PART B-ENGINEERING
(2023)
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
Claus O. W. Trost, Martin Krobath, Stanislav Zak, Rene Hammer, Thomas Krivec, Hans-Peter Gaenser, Thomas W. Trost, Anton Hohenwarter, Megan J. Cordill
Summary: Metallic foils are crucial in various applications and often part of multifunctional composites, where mechanical integrity is important. Accurate numerical material models, such as the Lemaitre-Chaboche model, are needed for precise simulations and lifetime prediction. This study fitted the material parameters of electrodeposited copper foils for the Lemaitre-Chaboche model and achieved good agreement with literature through nanoindentation and microstructural characterization. Furthermore, it found that the Tabor rule may not be applicable for estimating yield stress in metallic foils.
MATERIALS & DESIGN
(2023)
Article
Chemistry, Physical
Silvia Leitner, Gerald Winter, Juergen Klarner, Thomas Antretter, Werner Ecker
Summary: The investigation focuses on the quantitative and qualitative residual stress evolution in low-alloyed steel during heat treatment on three different length scales. The results show that macroscopic stresses up to 700 MPa and mesoscopic stresses up to Delta 50 MPa can be formed depending on the cooling procedure and extent of segregation. The study provides an overview of residual stresses in low-alloyed steels on different length scales and the results can be used for steel design.
Article
Metallurgy & Metallurgical Engineering
Andreas Karl Drexler, Florian Konert, Jonathan Nietzke, Emir Hodzic, Sergio Pastore, Josef Domitner, Michael Rhode, Christof Sommitsch, Thomas Boellinghaus
Summary: The hydrogen solubility in ferritic and martensitic steels is influenced by hydrostatic stress, pressure, and temperature. Compressive stress decreases solubility while tensile stress increases it. A pressure equivalent method is proposed to compensate for the effect of compressive stress on solubility in high-pressure containers. At low temperatures, trapping of hydrogen in the microstructure increases solubility, reaching a minimum at room temperature.
STEEL RESEARCH INTERNATIONAL
(2023)
