Article
Chemistry, Physical
Song Wang, Yi Kong, Li Chen, Yong Du
Summary: In this study, the effect of twelve <110> symmetric tilt grain boundaries (GBs) on the initial oxidation behavior of TiN was investigated using first-principles calculation method. It was found that Sigma 3 (111) GB has an extremely small energy, while other GBs have high energies. The oxygen adsorption results showed that GBs are chemically more favorable sites for oxygen, and Sigma 3 (111) GB can enhance the oxidation resistance of TiN. Additionally, Si doping can further improve the oxidation resistance of TiN with Sigma 3 (111) GB.
SURFACES AND INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Guangya Li, Yang Yang, Boyuan Gou, Jinyu Zhang, Jiao Li, Yaqiang Wang, Lingfei Cao, Gang Liu, Xiangdong Ding, Jun Sun
Summary: By controlling the defects of coherent twin boundaries (CTBs) through Cr segregation at kinks and grain boundaries (GBs), high strength and excellent structural-mechanical stability can be achieved, providing a new perspective for the design of purified Cu alloys.
Article
Nanoscience & Nanotechnology
Darshan Bamney, Laurent Capolungo
Summary: This work investigates the formation of adjoining twin pairs (ATPs) at grain boundaries (GBs) in hexagonal close-packed (hcp) metals, focusing on the co-nucleation (CN) of pairs of deformation twins. A continuum defect mechanics model is proposed to study the energetic feasibility of CN of ATPs resulting from GB dislocation dissociation. The model reveals that CN is preferred over the nucleation of a single twin variant for low misorientation angle GBs. Further analysis considering GB character and twin system alignment suggests that CN events could be responsible for ATP formation even at low m' values.
SCRIPTA MATERIALIA
(2024)
Article
Materials Science, Multidisciplinary
W. Xu, B. Zhang, K. Du, X. Y. Li, K. Lu
Summary: By means of cryogenic plastic deformation, a high proportion of relaxed grain boundaries can be generated in the Al-5Mg alloy, which is essential for stabilizing nanostructured alloys.
Article
Materials Science, Multidisciplinary
Jann-Erik Brandenburg, Luis A. Barrales-Mora, Sadahiro Tsurekawa, Dmitri A. Molodov
Summary: The migration behavior of grain boundaries with misorientations close to the & sigma;3 CSL orientation relationship in high purity Al bicrystals was investigated. It was found that the ability of some boundaries to move under capillary driving force depends on the initial boundary inclination. The measured migration activation enthalpy for one specific boundary was found to be the lowest among previous experiments in Al bicrystals of the same purity.
Article
Materials Science, Multidisciplinary
Chengyang Hu, Chengjie He, Xiaolong Gan, Xiangliang Wan, Feng Hu, Wen Zhou, Honghong Wang, Kaiming Wu
Summary: The influence of grain orientation and grain boundary on the deformation behavior of high-Mn steel was investigated through tensile tests, revealing significant effects of the grain boundary on the material properties.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Materials Science, Multidisciplinary
Yang Su, Songyang Han, Philip Eisenlohr, Martin A. Crimp
Summary: A new model has been proposed to predict the specific deformation system activity at grain boundaries, with promising results in testing. The optimized parameters indicate that both local and global stresses play a role in determining the accommodating systems and their activity. The model's predictions align well with literature values for alpha-titanium.
Article
Chemistry, Multidisciplinary
Peng-Fei Li, Yong Ai, Yu-Ling Zeng, Jun-Chao Liu, Zhe-Kun Xu, Zhong-Xia Wang
Summary: This study presents a pair of homochiral single-component organic ferroelectrics with high T-c values, showing superior ferroelectric properties and acoustic impedance characteristics, suitable for application in flexible smart devices.
Article
Chemistry, Physical
Xue-Qi Lv, Xiong-Ying Li, Hong-Bing Liu
Summary: Thermal diffusion plays an important role in determining the structures and properties of interfaces and nanolayers. Different deformation mechanisms apply in Al-Mg-Al nanolayers depending on the thermal diffusion temperature, with the formation of coherent Al/Mg interfaces significantly enhancing the tensile properties at high temperatures.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Abdul Wahid Shah, Seong-Ho Ha, Bong-Hwan Kim, Young-Ok Yoon, Hyun-Kyu Lim, Shae K. Kim
Summary: This study investigated the microstructural evolution and castability of Al-Mg-Si ternary alloys with different Si contents. The results showed changes in solidification process and grain size with increasing Si content in the alloys.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2021)
Article
Nanoscience & Nanotechnology
Changchun Zhang, Fengde Liu, Hongxin Wang
Summary: This study systematically investigated the tensile and fatigue properties of Laser directed energy deposition (LDED) samples under different stress directions. The pore distribution and microstructure of the samples were also studied. The results showed that the anisotropy of mechanical properties depended on the relationship between the prior-beta grains and the stress direction. The initiation of dislocation slip at alpha(GB) was easy, which led to crack initiation and propagation under horizontal stress. Additionally, larger pores caused a deterioration of mechanical properties under vertical stress.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Physics, Fluids & Plasmas
Danilo B. Liarte, Stephen J. Thornton, Eric Schwen, Itai Cohen, Debanjan Chowdhury, James P. Sethna
Summary: In this study, the researchers investigated the singular dynamical response of interacting liquids transitioning to a disordered solid, deriving scaling forms and extracting critical exponents, invariant scaling combinations, and analytical formulas for universal scaling functions near these transitions using effective-medium theory. Their scaling forms describe the behavior in space and time near the onsets of rigidity, including diverging length scales and timescales at the transitions for rigid and floppy phases and the crossover region.
Article
Chemistry, Multidisciplinary
Lisa S. Walter, Amelie Axt, James W. Borchert, Theresa Kammerbauer, Felix Winterer, Jakob Lenz, Stefan A. L. Weber, R. Thomas Weitz
Summary: In organic electronics, grain boundaries have a critical impact on charge transport. However, they are often hidden within the film and difficult to observe. By studying a minimal model system of thin films, it is found that grain boundaries can be either energetic barriers or valleys, and their influence is particularly pronounced at low charge-carrier densities. Furthermore, processing conditions that can control the type and energetic height of grain boundaries are identified.
Article
Chemistry, Physical
Giulia Arquilla, Alessandra Ceci, Girolamo Costanza, Maria Elisa Tata
Summary: This study analyzed the compressive behavior of Al honeycomb under pure normal stress and combined normal-shear stress. The mechanical behavior in compression by normal stress and in conditions of combined normal-shear stress was examined using a special pair of wedges. The results showed that as the load application angle increased, the shear resistance and tangential displacement of the honeycomb increased, contrary to normal behavior. The rotation angle of the cell also increased with the displacement of the crosshead and the application angle of the force.
Article
Materials Science, Multidisciplinary
Kun Dou, Yijie Zhang, Ewan Lordan, Alain Jacot, Zhongyun Fan
Summary: The solidification behavior of aluminum alloy inside the shot sleeve in the cold chamber high-pressure die casting process is studied using numerical modeling approach. The evolution and distribution of externally solidified crystals (ESCs) in the shot sleeve and their dependence on the piston motion profile are analyzed. The results show the impact of the piston motion profile on the distribution of ESCs.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Abhishek Biswas, Surya R. Kalidindi, Alexander Hartmaier
Summary: This study presents a hybrid method that combines the classical crystallographic yield locus method (CYL) with the crystal plasticity finite element method (CPFEM) to determine the anisotropic yield locus (YL) of a material. The hybrid method is shown to produce reliable results for diverse crystallographic textures, even with pronounced plastic anisotropy. The calibrated CYL method is used to construct a smooth yield function that can potentially be used in standard continuum plasticity methods for finite element analysis.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2022)
Article
Nanoscience & Nanotechnology
Shengli Li, Napat Vajragupta, Abhishek Biswas, Wenshen Tang, Hao Wang, Aleksander Kostka, Xinqi Yang, Alexander Hartmaier
Summary: The study indicates that the peak temperature and effective strain rate during the friction stir welding process influence the variation of prior austenite grain size, packet size, and block width in different subzones. The distribution of microhardness is directly correlated to the geometrically necessary dislocation density observed in the different zones.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
Mahesh R. G. Prasad, Abhishek Biswas, Napat Vajragupta, Alexander Hartmaier
Summary: This study investigates the influence of texture characteristics on the creep behavior of AM nickel-based superalloys and reveals that creep strength increases with decreasing texture intensities, reaching its maximum when the 001 fiber and cube textures are misaligned by 45 degrees.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2022)
Article
Materials Science, Multidisciplinary
Ronak Shoghi, Alexander Hartmaier
Summary: Trained machine learning algorithms can be used as efficient surrogate models for complex material behavior. This study investigates how to establish an optimal data-generation strategy to train machine learning yield functions with the least effort. It is shown that even for materials with significant plastic anisotropy, as few as 300 data points are sufficient to successfully train the machine learning yield function.
FRONTIERS IN MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Jan Schmidt, Abhishek Biswas, Napat Vajragupta, Alexander Hartmaier
Summary: In this study, a new data-oriented approach is proposed to model the material parameters of the anisotropic yield function based on different crystallographic textures using supervised machine learning methods. It is found that a regularization strategy is necessary to solve the non-uniqueness issue between the parameters and the plastic behavior. The trained ML models are able to accurately predict the plastic behavior of various textures.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2022)
Article
Chemistry, Physical
Aravindh Nammalvar Raja Rajan, Marcel Krochmal, Thomas Wegener, Abhishek Biswas, Alexander Hartmaier, Thomas Niendorf, Ghazal Moeini
Summary: The correlation between microstructural features and mechanical behavior of PBF-LB/M AlSi10Mg is investigated in this study. Heat treatment significantly affects the sub-grain morphology of the Si-rich phase and has a considerable impact on the mechanical behavior of the components. Predictive modeling using constitutive and plasticity models accurately predicts the tensile properties of AlSi10Mg.
Article
Materials Science, Ceramics
Liang Zhao, Jianguo Zhang, Junjie Zhang, Alexander Hartmaier, Tao Sun
Summary: This study reveals the ductile deformation mechanisms and microstructure evolution of 3C-SiC ceramic material during ultrasonic elliptical vibration-assisted diamond cutting. The formation of highly oriented high density stacking faults, along with suppressed amorphization and cracking, contributes to enhanced ductile material removal. Raman spectroscopy, transmission electron microscopy, and molecular dynamics simulations are used to elucidate the phase transformation and microstructure evolution mechanisms.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2022)
Article
Materials Science, Multidisciplinary
Liang Zhao, Jianguo Zhang, Yufan Fu, Junjie Zhang, Alexander Hartmaier, Tao Sun
Summary: The coupled thermal-mechanical properties of grain boundaries in polycrystalline 3C-SiC during diamond cutting at elevated temperatures were investigated using multi-scale simulations. The results showed that inter-granular fracture was suppressed, stacking fault formation was enhanced, healing ability of grain boundaries was increased, and ductile material removal was promoted at high temperatures.
MATERIALS & DESIGN
(2022)
Article
Chemistry, Physical
Abhishek Biswas, Dzhem Kurtulan, Timothy Ngeru, Abril Azocar Guzman, Stefanie Hanke, Alexander Hartmaier
Summary: This study focuses on investigating the mechanical behavior of low-nickel austenitic steel under high-pressure torsion fatigue (HPTF) loading, particularly the axial creep deformation observed in the experiment. The results show that a J2 plasticity model with an associated flow rule fails to describe the axial creep behavior, while a micromechanical model based on an empirical crystal plasticity law with kinematic hardening described by the Ohno-Wang rule can accurately match the HPTF experiments. Therefore, our findings confirm the versatility of crystal plasticity combined with microstructural models in describing the mechanical behavior of materials under reversing multiaxial loading situations.
Article
Materials Science, Multidisciplinary
Ashish Chauniyal, Rebecca Janisch
Summary: Gamma/gamma interfaces play a crucial role in driving plastic deformation in lamellar TiAl alloys. The presence of different variants of gamma/gamma twin interfaces, such as coherent and semicoherent interfaces, results in variations in deformation behavior. It has been found that the coherency state of the gamma/gamma interfaces leads to preferential nucleation and affects the strength of the lamellar microstructure. These findings contribute to the future design of alloy microstructures based on interface types and coherency states.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Mahdieh Shahmardani, Ruslan Logvinov, Tomas Babinsky, Stefan Guth, Shubhadip Paul, Abhishek Biswas, Napat Vajragupta, Alexander Hartmaier
Summary: This work investigates the cyclic deformation behavior of additively manufactured 316L austenitic stainless steel. Specimens of 316L steel are produced using powder bed fusion of metals with laser beams (PBF-LB/M) with different parameters, and cyclic strain tests are conducted to assess their deformation behavior under cyclic loads at room temperature. Additionally, a micromechanical model based on representative volume elements (RVE) is developed to simulate the deformation-dependent internal stresses within the microstructure. The study reveals significant effects of specimen orientation and crystallographic texture on cyclic behavior, with a minor influence of grain shape.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
G. Tolooei Eshlaghi, G. Egels, S. Benito, M. Stricker, S. Weber, A. Hartmaier
Summary: This article presents a robust and comprehensive approach for reconstructing the three-dimensional microstructure of two-phase materials based on electron backscatter diffraction (EBSD) maps from orthogonal surfaces. The method involves processing surface maps using spatial correlation functions combined with principal component analysis (PCA) to generate a representative fingerprint. The approach is demonstrated to accurately describe the microstructure of a metastable austenitic steel and can generate statistically equivalent microstructures.
FRONTIERS IN MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Santiago Benito, Gero Egels, Alexander Hartmaier, Sebastian Weber
Summary: The microstructure plays a crucial role in connecting the thermodynamic, compositional, and kinetic stochasticity with macroscopic behavior. In this study, we propose a fast first-order variogram as a statistical tool to comprehensively describe chemical segregations in metallic materials. We discuss its derivation, application, advantages, and limits, and compare it with popular texture characterization techniques. This method provides a simple yet powerful way to characterize the severity of micro and mesosegregations and quantify their influence on material behavior.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Jan Schmidt, Alexander Hartmaier
Summary: This article proposes a new generic descriptor for crystallographic texture that allows an explicit consideration of the microstructure in data-driven constitutive modeling. It provides a pathway to microstructure-sensitive data-driven constitutive modeling.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Nanoscience & Nanotechnology
Aravindh Nammalvar Raja Rajan, Marcel Krochmal, Mahdieh Shahmardani, Thomas Wegener, Alexander Hartmaier, Thomas Niendorf, Ghazal Moeini
Summary: The AM process continues to attract attention in industrial and academic research due to its high degrees of design freedom and flexibility in the production process. However, the use of AM-processed components for parts under cyclic loading is limited by significant variance in cyclic behavior and the effects of AM-associated defects. This study examines and predicts the low-cycle fatigue behavior of AlSi10Mg parts produced by laser-based powder bed fusion in both the as-built and direct-aged condition using experiments and microstructure-sensitive models. The applied modeling framework accurately predicts the LCF behavior of AlSi10Mg under various strain amplitudes and ratios for both conditions.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
