Article
Materials Science, Multidisciplinary
K. E. N'souglo, K. Kowalczyk-Gajewska, M. Marvi-Mashhadi, J. A. Rodriguez-Martinez
Summary: In this paper, the effect of initial texture on multiple necking patterns in ductile metallic rings subjected to rapid radial expansion was investigated using finite element calculations. The material behavior was modeled using the elasto-viscoplastic single crystal constitutive model developed by Marin specialIntscript. The polycrystalline microstructure of the ring was generated using random Voronoi seeds. The results showed that the spatial distribution of grains, grain size, and initial texture have significant effects on the formation of necks.
MECHANICS OF MATERIALS
(2023)
Article
Engineering, Mechanical
M. Vieira de Carvalho, I. A. Rodrigues Lopes, F. M. Andrade Pires
Summary: This contribution investigates the modelling of failure in polycrystalline materials due to the nucleation and propagation of cohesive cracks at the micro-scale. A two-scale formulation and a fracture-based computational homogenisation procedure are proposed to analyze failure and obtain homogenized mechanical properties. Numerical examples confirm the effectiveness of the methods and investigate the influence of microscopic boundary conditions and deformation mechanisms on intergranular crack propagation.
INTERNATIONAL JOURNAL OF PLASTICITY
(2023)
Article
Engineering, Mechanical
Bjorn Hakon Frodal, Susanne Thomesen, Tore Borvik, Odd Sture Hopperstad
Summary: This study presents a crystal plasticity model that considers the effects of voids or micro-cracks on damage evolution and ductile failure in a single crystal. By simulating the behavior of four different aluminum alloys, the unique properties of each alloy, such as yield strength, work hardening, grain structure, and tensile ductility, are investigated. The capability of the proposed crystal plasticity model is demonstrated through comparison of finite element simulations and experimental tests, showing good agreement between the two and accurate prediction of various shapes of failed specimens.
INTERNATIONAL JOURNAL OF PLASTICITY
(2021)
Article
Mathematics, Applied
Joao A. Marques da Silva, Miguel Vieira de Carvalho, Rui P. Cardoso Coelho, Igor A. Rodrigues Lopes, Francisco M. Andrade Pires
Summary: This contribution analyzes the convergence behavior of representative volume elements (RVEs) with an increasing number of crystalline grains. The influence of crystallographic slip and mechanically induced martensitic formation is studied. Instead of analyzing a single micromechanical model, the representativeness of the RVEs is assessed through distinct macroscopic simulations. A computationally efficient Taylor's condition (FE-T) is assumed to make the convergence analysis feasible. The results showed that the macroscopic response converges regardless of whether the martensitic transformation is considered or not.
FINITE ELEMENTS IN ANALYSIS AND DESIGN
(2023)
Article
Engineering, Mechanical
Paul G. Christodoulou, Sylvain Dancette, Ricardo A. Lebensohn, Eric Maire, Irene J. Beyerlein
Summary: This study investigates the effect of crystallographic orientation and applied triaxiality on the growth of intragranular voids using two 3D micromechanics methods. The results show that loading type significantly influences void growth rate, and void growth is slower in polycrystals compared to single crystals. Furthermore, at the highest triaxiality tested, the correlation between crystal orientation and void growth rate in polycrystals strengthens.
INTERNATIONAL JOURNAL OF PLASTICITY
(2021)
Article
Materials Science, Multidisciplinary
M. Cottura, B. Appolaire, A. Finel, Y. Le Bouar
Summary: Microstructure evolutions in Ni-base superalloys under [110] creep loading were investigated using 3D and 2D phase field simulations. It was found that minor misorientations of the tensile axis lead to rafting, while loading along a perfectly aligned [110] direction results in a microstructure composed of rod-like precipitates. The direction of the mechanical load significantly affects the evolution of microstructure and macroscopic creep behavior.
Article
Materials Science, Multidisciplinary
Jinhu Zhang, Xuexiong Li, Dongsheng Xu, Chunyu Teng, Hao Wang, Liang Yang, Hongtao Ju, Haisheng Xu, Zhichao Meng, Yingjie Ma, Yunzhi Wang, Rui Yang
Summary: The study investigated variant selection under specific applied stresses during precipitation of alpha plates from prior-beta matrix in Ti-6Al-4V through 3D phase field simulations. It was found that external stresses have a profound influence on variant selection, with a stronger preference for fewer variants under shear stresses in certain directions. This study provides insights into optimizing the mechanical properties of the alloy through thermomechanical processing based on the findings from phase field simulations and crystal plastic finite element simulation.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Mikhail Khadyko, Bjorn Hakon Frodal, Odd Sture Hopperstad
Summary: The study proposed a regularized model of porous crystal plasticity, which can describe the plastic behavior of materials under various stresses and be applied in a finite element code. Simulation results demonstrate the model's capability to effectively explain the interaction between different modes of strain localization, as well as the initiation and propagation of ductile fracture.
INTERNATIONAL JOURNAL OF FRACTURE
(2021)
Article
Automation & Control Systems
Ikumu Watanabe, Toshiro Amaishi
Summary: The anisotropic deformation behavior of a polycrystalline billet during micro-extrusion was investigated using three-dimensional finite element analyses. The study found that the deformation is influenced by the anisotropy of crystal grains and the grain size. The crystallographic texture of the extruded billet also plays a role in reducing anisotropic deformation, especially in the case of large grains.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Lola Lilensten, Stoichko Antonov, Baptiste Gault, Sammy Tin, Paraskevas Kontis
Summary: This study investigates the differences in creep behavior of polycrystalline Ni-based superalloys with two different Nb contents, attributing the mechanical performance variation to phase transformations along planar faults. The presence of stacking faults and their composition in the alloys are analyzed using electron channeling contrast imaging and atom probe tomography, revealing insights into the underlying mechanisms of creep strain rate differences. The findings suggest a potential atomic-scale driven alloy design approach for enhancing creep resistance by promoting local phase transformations along planar faults at 750 degrees C.
Article
Engineering, Mechanical
Xu Long, Kainan Chong, Yutai Su, Chao Chang, Liguo Zhao
Summary: A mesoscopic constitutive model coupled with crystal plasticity and damage is established to investigate the plastic deformation and damage-induced degradation of polycrystalline materials under cyclic loading. The proposed model is verified through a single-element model containing one grain. The stress, strain states, and damage evolution of polycrystals under cyclic loading are comprehensively investigated, and the constitutive parameters in the model are calibrated against experimental results. The simulation results show that considering damage can more accurately describe the strength degradation of polycrystals under cyclic loading.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Materials Science, Multidisciplinary
Yongcheng Huo, Yu Liu, Shungui Zuo, Bo Wang, Qiang Li
Summary: A finite element model was used to predict phase transformation plasticity (TP) and reveal the factors influencing TP. A formula for predicting the TP coefficient K was proposed and verified using experimental data. The function f(φ) describing the evolution of TP with the transformed fraction φ was discussed and verified.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Boqian Sun, Daming Chen, Yuan Cheng, Weidong Fei, Danyu Jiang, Sufang Tang, Guangdong Zhao, Juntao Song, Chenlin Hou, Wenzheng Zhang, Shiqi Wu, Yu Yang, Mingyi Tan, Jie Zhang, Daqing Wei, Chaowei Guo, Wei Zhang, Shun Dong, Shanyi Du, Jiecai Han, Jian Luo, Xinghong Zhang
Summary: This article discusses the development of sugar-derived isotropic nanostructured polycrystalline graphite (SINPG), which achieves excellent plasticity by activating the rotation of nanoscale grains, resulting in high compressive strength and plastic strain. This new material is of great significance for various applications in different fields.
ADVANCED MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Hai Wu, Cuili Guo
Summary: Pure SSZ-13 zeolite has been synthesized by converting ZSM-5 without water. The addition of SSZ-13 seeds avoids the generation of MOR phase and reduces the size of the prepared samples.
Article
Engineering, Mechanical
Hyuk Jong Bong, Jinwoo Lee, Myoung-Gyu Lee
Summary: In this study, a multiscale model was developed to predict the cyclic loading behaviors of a wrought magnesium alloy. The model accounted for temperature dependency and introduced the concept of variable residual twin fraction. The accuracy of the model was validated by comparing with experimental data.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Materials Science, Multidisciplinary
Tahereh Zargar, Fazlollah Sadeghi, Jong Wan Kim, Jae Sang Lee, Yoon-Uk Heo, Chang Hee Yim
Summary: The Thermo-Calc software was used to predict the M-shaped delta-ferrite content in continuously cast 304 austenitic stainless steel slab, with the moving-boundary model showing accurate results when compared to observations. Analysis of different cooling rates revealed a more significant reduction in delta-ferrite under fast solidification rates.
METALS AND MATERIALS INTERNATIONAL
(2022)
Article
Materials Science, Ceramics
Minoru Maeda, Yoon-Uk Heo, Jun Hyuk Choi, Dipak Patel, Su-Hun Kim, Seungyong Hahn, Jung Ho Kim, Seyong Choi
Summary: Powder processing by ball milling is an effective method for structural modification of superconducting materials. Low-rotation shaker was used to achieve structural modification by controlling processing parameters and enhancing energy transfer. The morphological changes of the processed powders influenced the void structure and composition of the materials.
CERAMICS INTERNATIONAL
(2022)
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
Metallurgy & Metallurgical Engineering
Thi Thanh Tram Trang, Chang-Gon Jeong, Dongwon Lee, Yoon-Uk Heo
Summary: The effect of extended intercritical annealing time on the microstructure and tensile properties of a medium Mn steel is studied. Nanosized lamellar structures consisting of tempered-alpha ' martensite and retained austenite are formed after intercritical annealing. The fraction of cementite and fresh alpha ' martensite increases with extended annealing time, leading to reduced austenite fraction after quenching.
STEEL RESEARCH INTERNATIONAL
(2023)
Article
Metallurgy & Metallurgical Engineering
Fazlollah Sadeghi, Tahereh Zargar, Muhamad Rasyad Arkan Lahino, Hyeju Kim, Sang-Hum Kwon, Yoon-Uk Heo, Jae Sang Lee, Chang Hee Yim
Summary: The influence of reheating temperatures on hot ductility was investigated in two Ni-, Mo-, and Cu-containing low-carbon steels. It was found that higher reheating temperatures resulted in relatively poor hot ductility, while lower temperatures improved the ductility. In addition, the alloy composition and the existence of preformed precipitates were found to affect the hot ductility.
STEEL RESEARCH INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Hyeonseok Kwon, Praveen Sathiyamoorthi, Manogna Karthik Gangaraju, Alireza Zargaran, Jaemin Wang, Yoon-Uk Heo, Stefanus Harjo, Wu Gong, Byeong-Joo Lee, Hyoung Seop Kim
Summary: In this work, a novel Fe-based medium-entropy alloy was designed based on the characteristics of maraging steels. By a single-step aging at 650 celcius for 10 min, the alloy exhibited microstructures consisting of high-density nanoprecipitates and reverted FCC phase, resulting in ultrahigh yield strength and good ductility.
Article
Chemistry, Physical
Eun Seong Kim, K. R. Ramkumar, G. M. Karthik, Sang Guk Jeong, Soung Yeoul Ahn, Praveen Sathiyamoorthi, Hyojin Park, Yoon-Uk Heo, Hyoung Seop Kim
Summary: In this study, the microstructural evolution, tensile properties, and deformation behavior of additively manufactured equiatomic CoCrFeMnNi high entropy alloy (HEA) were investigated at a cryogenic temperature of 77 K. The results showed that the HEA processed by direct energy deposition (DED) exhibited excellent strength and ductility at 77 K, with exceptional strain hardening, compared to the laser powder bed fusion (LPBF) and wrought samples. The formation of deformation twinning in addition to dislocation slip was observed as the deformation mechanism at 77 K.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Gang Hee Gu, Yoon-Uk Heo, Hyeonseok Kwon, Soung Yeoul Ahn, Sujung Son, Peyman Asghari-Rad, Hyoung Seop Kim
Summary: Materials manufactured through conventional powder metallurgy techniques often have inferior tensile properties. However, a recently developed cold-consolidation technique using powder high-pressure torsion has produced well-manufactured structures with ultra-high tensile properties. In this study, the technique was used to fabricate a multi-material Inconel 718/CoCrFeMnNi/Inconel 718 layered structure, which exhibited superior tensile properties compared to monolithic systems. These findings demonstrate the potential of the cold-consolidation technique to manufacture multi-layered and gradient multi-functional structures with excellent mechanical response under tensile stress.
SCRIPTA MATERIALIA
(2023)
Article
Nanoscience & Nanotechnology
Rae Eon Kim, Gangaraju Manogna Karthik, Auezhan Amanov, Yoon-Uk Heo, Sang Guk Jeong, Gang Hee Gu, Hyojin Park, Eun Seong Kim, Do Won Lee, Hyoung Seop Kim
Summary: This study proposes a new strategy to achieve a superior gradient structure in 316L stainless steel fabricated by laser powder bed fusion (LPBF) through annealing and ultrasonic nanocrystal surface modification (UNSM). The post-LPBF annealing treatment disrupts the cellular dislocation structure, resulting in optimized materials for a gradient structure. The resulting gradient structure after UNSM treatment has a thicker gradient layer with significant strain partitioning between domains, leading to superior strength-ductility synergy compared to LPBF-UNSM samples.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
T. T. T. Trang, Dongwon Lee, Yoon-Uk Heo
Summary: This study provides a detailed investigation of the twin structure in martensitic steels, clarifying the existence of ledge-typed twin boundaries at the {112} twin boundaries. The ledges occur on {110} planes and exhibit a gradual transition from the primary (112) twin plane to secondary twin planes (011) and (110).
Article
Chemistry, Physical
Minoru Maeda, Akiyoshi Matsumoto, Gen Nishijima, Yoon-Uk Heo, Seungyong Hahn, Sangjin Lee, Seyong Choi, Jung Ho Kim
Summary: In this study, the researchers proposed a method of regulating porous properties using magnesium powder blending. Through a detailed investigation, they found a significant correlation between various particle parameters, impurities, superconducting transition temperature, and current carrying capacity, with the porous properties. The blending of raw powders with spherical shape allowed for tuning of morphological structures and crystallinities inside the cores of the MgB2 superconducting wires, resulting in superior superconducting properties. This finding provides valuable insights for the widespread use and application of superconducting materials.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Gang Hee Gu, Hyeonseok Kwon, Yongju Kim, Farahnaz Haftlang, Yoon-Uk Heo, Hyoung Seop Kim
Summary: Carbon-added equi-atomic CoCrFeMnNi high-entropy alloys exhibit bake hardening effect and show better performance compared to conventional bake-hardenable materials, providing possibilities for the industrialization of various interstitial HEA systems as well as carbon-added CoCrFeMnNi HEAs.
MATERIALS & DESIGN
(2023)
Article
Nanoscience & Nanotechnology
Chang-Gon Jeong, T. T. T. Trang, Youngyun Woo, Eun Yoo Yoon, Youngseon Lee, Yoon- Uk Heo
Summary: The effect of cooling rate on the microstructure and tensile properties of multiphase steel was investigated. Increasing the cooling rate significantly improved the tensile properties without sacrificing elongation, which was attributed to the increased fraction of bainite. All specimens exhibited similar fraction and mechanical stability of gamma.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Review
Microscopy
T. T. T. Trang, Yoon-Uk Heo
Summary: Nanosized precipitates are crucial for strengthening metallic alloys. The initial metastable precipitates in these alloys undergo a phase transition to stable phases during heat treatment, which can be studied using a transmission electron microscope.
Article
Nanoscience & Nanotechnology
Jeong Min Park, Hyeonseok Kwon, Jungho Choe, Kyung Tae Kim, Ji-Hun Yu, Yoon-Uk Heo, Hyoung Seop Kim
Summary: This study presents a guideline for alloy design in additive manufacturing, aiming to produce high-quality products with excellent mechanical performance by utilizing the unique segregation engineering of LPBF-driven microstructures. Mo-doping enhances the strength and ductility of ferrous medium-entropy alloys.
SCRIPTA MATERIALIA
(2023)
