Article
Materials Science, Multidisciplinary
Masoud Moshtaghi, Mahdieh Safyari
Summary: The joint effect of temperature and strain rate on hydrogen embrittlement properties of martensitic steel was investigated. It was found that at 50 °C, the elongation loss initially increased and then decreased with decreasing strain rate. This study provides the first report that at low strain rates, the temperature can mitigate hydrogen embrittlement susceptibility by increasing hydrogen effusion to the material surface and releasing a significant amount of hydrogen before the yield point. At 25 °C, the elongation loss increased with decreasing strain rate, as hydrogen could interact with mobile dislocations at lower strain rates, eventually leading to hydrogen-induced fracture. Additionally, intergranular cracks were observed, which can be attributed to prior austenite grain boundaries acting as paths for hydrogen-induced cracking.
Article
Materials Science, Multidisciplinary
Karim Ismail, Astrid Perlade, Pascal J. Jacques, Thomas Pardoen
Summary: DP steels with a 'Thomas-fibers' type platelet martensite morphology exhibit significantly larger cracking resistance compared to corresponding equiaxed microstructures, offering a new path to optimize fracture toughness without compromising strength and/or changing the chemical composition. The superior cracking resistance is shown to originate from a remarkable resistance to damage nucleation related to the alignment of the platelets upon deformation and from their small size.
Article
Engineering, Mechanical
Ao Tang, Haiting Liu, Ran Chen, Guisen Liu, Qingquan Lai, Yong Zhong, Li Wang, Jeff Wang, Qi Lu, Yao Shen
Summary: The study revealed that different volume fractions and distributions of martensite can lead to different damage modes in ferrite-martensite dual-phase steels. Through mesoscale stress and strain analysis, we identified the origins of these damage modes.
INTERNATIONAL JOURNAL OF PLASTICITY
(2021)
Article
Materials Science, Multidisciplinary
Loic Sorbier, Hedwige Poncet, Vincent Lecocq, Guillaume Maillet, Marwa Moula, Vincent Le Corre
Summary: The proposed method accurately measures the local porosity of porous samples from scanning electron microscopy images, allowing for quantitative characterization of porosity fluctuations and their link with preparation parameters. The methodology shows good agreement with global porosity measured by mercury intrusion porosimetry, demonstrating its effectiveness in studying porous materials.
MICROSCOPY AND MICROANALYSIS
(2021)
Article
Microscopy
R. Podor, J. Mendonca, J. Lautru, H. P. Brau, D. Nogues, A. Candeias, P. Horodysky, A. Kolouch, M. Barreau, X. Carrier, N. Ramenatte, S. Mathieu, M. Vilasi
Summary: A new high-temperature detector is used in combination with heating stages for collecting backscattered electrons, evaluating material transformations at high temperatures. It offers good opportunities for high-temperature experiments in various atmospheres, potentially adaptable to any type of SEM.
JOURNAL OF MICROSCOPY
(2021)
Article
Physics, Multidisciplinary
Paolo Glorioso, Sean A. Hartnoll
Summary: Heat supplied to a metal is absorbed by the electrons and transferred to the lattice. In conventional metals, energy is released to the lattice through phonons emitted from the Lindhard continuum. However, in a 'bad' metal with a short mean free path, the low energy Lindhard continuum is destroyed. To describe energy transfer to the lattice in these cases, a general Kubo formula is obtained for the energy relaxation rate based on the electronic density spectral weight.
Article
Materials Science, Multidisciplinary
Navaira Izhar, M. N. S. Qureshi, J. K. Shi, H. A. Shah
Summary: In this study, the investigation of obliquely propagating nonlinear fast and slow magnetosonic wave modes in a hot non-Maxwellian dissipative plasma was conducted. Modified temperatures for the non-extensive Q- and (r, q)-distributions were derived to correspond to the physical properties of such plasmas. The linear dispersion relation and Kadomstev-Petvashvilli-Burgers equation were derived using the reductive perturbation technique, and the effect of non-extensive parameter Q, spectral indices (r, q), and kinematic viscosity ν on the linear and nonlinear propagation of the wave modes was investigated. The results show significant modifications in the linear and nonlinear propagation of fast and slow magnetosonic waves in non-Maxwellian plasmas.
RESULTS IN PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
E. Espinosa, A. Sardar, C. H. M. Simha, A. Bardelcik
Summary: The study presents a framework for digitizing Dual-Phase (DP) steel microstructures into three-dimensional Representative Volume Elements (RVEs), using microscopy images and finite element models. A comprehensive mean-field model is employed to obtain material performance curves, and the relationship between plastic strain and martensite islands at the onset of necking is demonstrated. The iso-work assumption in one-dimensional mean-field models for DP steel as a two-phase composite is also discussed.
MECHANICS OF MATERIALS
(2021)
Article
Engineering, Multidisciplinary
Andrzej M. Zak, Anna Wieczorek, Agnieszka Chowaniec, Lukasz Sadowski
Summary: The method of assessing porosity using SEM images is ineffective when the substrate and coating have different average atomic numbers, resulting in different contrast of backscattered electrons. Previous analyses relied on manual distinction of microstructure elements and selective thresholding, which is subjective and prone to errors. A new method was presented using both backscattered electron images and elemental maps for distinguishing epoxy resin from hydrated cement-based substrate, with the help of multivariate comparative analysis, making detection and analysis more accurate and reliable.
Article
Nanoscience & Nanotechnology
Tobias Robl, Christian Krempaszky, Alexander Fillafer, Ewald Werner
Summary: The unloading behavior of ferritic-martensitic dual-phase steels is complex and influenced by various parameters, with martensite volume fraction and phase strength contrast having the largest impact. Additionally, the distribution of martensite in the microstructure, residual stresses, and plastic pre-deformation caused by sheet production significantly affect the unloading behavior.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Bo Gao, Rong Hu, Zhiyi Pan, Xuefei Chen, Yi Liu, Lirong Xiao, Yang Cao, Yusheng Li, Qingquan Lai, Hao Zhou
Summary: By tailoring the microstructural features, steels with excellent strength and ductility can be achieved. In this work, laminate dual-phase (DP) steels with high martensite content were produced, leading to significantly improved strength and ductility. The influence of laminate structure and high martensite content were discussed, along with the strengthening and ductilizing mechanisms.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Physics, Applied
Wei Sun, Yasunori Goto, Takuma Yamamoto, Keiichiro Hitomi
Summary: A deep learning model was developed in this study to predict the 3D profile of high-aspect-ratio channel holes using electron microscopy images, improving the accuracy and sensitivity.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Eunji Song, Gun-Hee Lee, Hansol Jeon, Bong June Park, Jung-Gu Lee, Ju-Young Kim
Summary: This study measured stretch-flangeability on dual-phase and complex-phase steels using the hole-expansion ratio, and introduced nanoindentation to assess the hardness of constituent phases. It was found that the hardness ratio of the hard to soft phase is crucial for formability, and the hardness of the GND layers in soft phases plays a critical role in determining strain disparity under deformation. The study suggests that the GND layer acts as a stress-dispersion layer and is important for formability.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Chemistry, Physical
Krzysztof Bzowski, Lukasz Rauch, Maciej Pietrzyk, Marcin Kwiecien, Krzysztof Muszka
Summary: The development of a reliable model for phase transformations in steels poses significant challenges, involving metallurgical aspects, numerical solutions, and implementation. The model proposed in this study focuses on austenitic and ferritic transformations, aiming to reduce computing time without compromising accuracy and reliability. By utilizing Representative Volume Element and assuming carbon diffusion as the main driving force, along with a coupled finite element-level set method, the model successfully describes the growth of new phases and is verified and validated through experimental data comparison.
Article
Nanoscience & Nanotechnology
D. Frometa, N. Cuadrado, J. Rehrl, C. Suppan, T. Dieudonne, P. Dietsch, J. Calvo, D. Casellas
Summary: The influence of microstructure on fracture toughness of two industrially processed 1000 MPa dual-phase (DP) steel grades was investigated. Results showed that the strain-induced transformation of retained austenite to martensite may be detrimental to cracking resistance, while the connectivity of hard secondary phases and proportion of soft phase play a major role in fracture toughness. Microstructural tailoring can balance global formability and cracking resistance of high strength DP steels.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)