Article
Nanoscience & Nanotechnology
Minghong Li, Lilin Wang, Haiou Yang, Shuya Zhang, Xin Lin, Weidong Huang
Summary: Selective laser melting (SLM) has unique advantages in manufacturing oxide dispersion strengthened alloys. This study comparatively investigates the microstructure and mechanical properties of Inconel 625 alloy and Y2O3 strengthened Inconel 625 alloy prepared by SLM. The results show that the Y2O3/Inconel 625 specimen has better density, grain structure, and mechanical properties.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
S. Ganesh, P. Sai Karthik, M. Ramakrishna, A. Reddy, S. B. Chandrasekhar, R. Vijay
Summary: In this study, nitrogen-containing and nickel alloyed austenitic oxide dispersion strengthened steel was produced through ball milling and hot extrusion, resulting in a fully homogenous austenitic phase with ultrafine grain size and bimodal distribution. The processed steel exhibited high yield strength and fracture strain at room temperature, attributed to grain boundary and Orowan strengthening mechanisms.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
X. Cheng, K. Jing, Z. M. Xie, R. Liu, X. B. Wu, X. P. Wang, Q. F. Fang, C. S. Liu
Summary: By in-situ forming nanoscale ZrC particles in W-Zr-C alloy, the low-temperature toughness and high-temperature stability of the alloy can be improved. The alloy exhibits ductility at 200 degrees C, with high ultimate tensile strength and total elongation at 300 degrees C. After annealing, the alloy retains high UTS and TE, with a higher recrystallization start temperature compared to pure W.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Liying Yao, Yijie Huang, Yimin Gao, Yefei Li, Xiaoyu Huang, Yiran Wang, Qingkun Liu, Changmeng Zhou
Summary: The hot deformation behavior of nanostructural oxide dispersion-strengthened (ODS) Mo alloy was investigated in this study. The results showed that the flow behavior is greatly affected by the deformation temperatures and strain rates, exhibiting typical hardening, softening, and steady stages. Constitutive equations and hot processing maps were established to predict the flow stress and develop stability zones.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Mi Zhao, Boyang Xu, Peng Zhang, Junjie Xu, Yong Jiang, Feng Liu, Youwei Yan
Summary: A Y-Ti-O oxide-dispersion-strengthened (ODS) Cu alloy was successfully fabricated through mechanical alloying and spark plasma sintering. The optimization of raw powder composition and ball-milling time allowed for the high density precipitation of ultra-fine Y-Ti-O nano-oxides. However, further improvement is needed for the dispersion of nano-oxides.
MATERIALS CHARACTERIZATION
(2022)
Article
Materials Science, Multidisciplinary
M. C. Yang, X. H. Du, C. X. Shi, W. P. Li, J. Y. Zhang, R. F. Zu, S. Yuan, T. H. Chou, J. C. Huang, G. S. Duan, B. L. Wu, J. Sun
Summary: Explored the mechanical response of a cold-rolled complex alloy at 700 degrees C as a function of ageing time, finding that long-term ageing led to an ultrafine-scaled recrystallized microstructure and high-content ordered precipitates. Transmission electron microscopy observations confirmed that abundant stacking faults and deformation induced twins were mainly responsible for the observed extra strain-hardened behavior during the critical plastic straining stage.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Liying Yao, Yimin Gao, Yefei Li, Xiaoyu Huang, Yiran Wang, Yijie Huang
Summary: The nanostructural oxide dispersion strengthened (ODS) Mo alloy was successfully fabricated through mechanical alloying and spark plasma sintering. The study found that the mechanical alloying process refines the powder and promotes the dissolution of interstitial atoms, but introduces impurities. The optimized spark plasma sintering parameters resulted in high relative density and improved mechanical properties.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Hongchao Li, Jun Wang, Ni Deng, William Yi Wang, Ruihao Yuan, Jinshan Li
Summary: This study investigates an ultra-strong high-entropy alloy (HEA) reinforced by a pearlite-like lamellar structure. The results demonstrate that this alloy exhibits excellent mechanical properties, making it promising for technological applications.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Muthuchamy AyyappaRaj, Digvijay Yadav, Dinesh K. Agrawal, Raja Annamalai Arunjunai Rajan
Summary: By adding La(2)O(3) to WHA with a ternary composition of W-7Ni-3Fe, this study achieved control over sintered density, grain size, hardness, and UTS, providing important references for the preparation of the alloy.
Article
Chemistry, Physical
Mustafa Tekin, Gokhan Polat, Y. Eren Kalay, Hasan Kotan
Summary: Nanocrystalline CoCrFeNi high entropy alloys with 1 and 4 wt% nanosized Y2O3 were synthesized and annealed at different temperatures. The addition of Y2O3 nanoparticles improved the grain size stability and hardness of CoCrFeNi at high temperatures, showing potential for enhancing its mechanical properties.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Nuclear Science & Technology
Yusuke Shimada, Masataka Mizumoto, Yoshimitsu Hishinuma, Ken-ichi Ikeda, Kenta Yoshida, Hiroyuki Noto, Bing Ma, Takeo Muroga, Yasuyoshi Nagai, Toyohiko J. Konno
Summary: The distribution of Y2O3 in oxide dispersion strengthened Cu alloys is closely related to the microstructural changes during mechanical alloying and heat treatment processes, and optimizing these processes can improve the alloy's performance.
FUSION ENGINEERING AND DESIGN
(2021)
Article
Nanoscience & Nanotechnology
Le Zong, Liujie Xu, Chunyang Luo, Zhou Li, Yunchao Zhao, Zhaoning Xu, Chenhui Zhu, Shizhong Wei
Summary: WMoNbTaV-1ZrO(2) refractory high-entropy alloy was successfully prepared by adding m-ZrO2 particles, which significantly increased the strength and plasticity of the alloy. The high strength was mainly due to the inherent strength in the alloy and grain boundary strengthening caused by the addition of m-ZrO2 particles.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
M. Mesbah, A. Fattahi, A. R. Bushroa, G. Faraji, K. Y. Wong, W. J. Basirun, A. Fallahpour, B. Nasiri-Tabrizi
Summary: Ultrafine-grained ZK60 magnesium tubes were successfully fabricated using parallel tubular-channel angular pressing (PTCAP) process. The mechanical properties of the processed tubes were accurately estimated using Radial Basis Function (RBF) and Multi-Layer Perceptron (MLP) artificial neural networks. The processed tubes showed refined microstructure and increased mechanical strength and ductility compared to the as-received specimen.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
SeungHyeok Chung, Ji Ho Shin, Ho Jin Ryu
Summary: This study investigates the dispersoid formation and microstructural evolution in an oxide dispersion-strengthened CoCrFeMnNi high-entropy alloy through a newly designed multistep sintering process. It is found that the multistep sintering process leads to the formation of finer FCC Y2O3 dispersoids and a refined grain structure, compared to the conventional single-step sintering.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
M. Sivakumar, Shyam Kanta Sinha, Arup Dasgupta, Sufyan M. Shaikh
Summary: The Alloy 617 ODS powder, milled with high energy, was consolidated by Spark Plasma Sintering (SPS) and subsequently annealed at 650°C and 1050°C. The microstructure showed a bimodal structure with ultra-fine grains surrounded by coarse grains, providing both ductility and strength. The annealed sample at 650°C exhibited <111> annealing texture while the texture was randomized at 1050°C annealing temperature. The presence of M23C6, M6C, Al2O3, fine and uniform Y3Al5O12, Y4Al2O9, and a complex oxide rich in Ni, Y, Al, and O was observed in both as-sintered and annealed samples.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Wenke Wang, Jaimyun Jung, Chao Cui, Wenzhen Chen, Yang Yu, Peng Li, Wencong Zhang, Renlong Xiong, Hyoung Seop Kim
Summary: This work investigated the anisotropy variation of tensile flow stress for AZ31 magnesium alloys at different temperatures and tensile strains using the visco-plastic self-consistent model. The results showed that the anisotropy of flow stress weakened with increasing temperature and exhibited a slightly increasing stage followed by a continuously decreasing stage with increasing strain. Activation of basal slip and tension twinning contributed to the development of a (0002)//LD type texture during tension deformation, while activation of prismatic slip produced a < 10-10 >//LD type texture. The study found that the macroscopic average resolved shear stress decreased significantly with increasing temperature or strain, resulting in the decline of the tension deformation behavior anisotropy.
METALS AND MATERIALS INTERNATIONAL
(2023)
Article
Metallurgy & Metallurgical Engineering
Minseok Gwak, Jun Young Park, Sang Guk Jeong, Jae Bok Seol, Hyokyung Sung, Seokhwan Kim, Hyoung Seop Kim, Jung Gi Kim
Summary: In this study, the properties of Fe-Si alloy samples processed by additive manufacturing (AM) were estimated using the response surface methodology (RSM). Quadratic polynomial models based on RSM successfully predicted the density and hardness of AM-processed Fe-4.5Si alloy samples. The optimal conditions to manufacture Fe-4.5Si samples with the highest density and hardness combination were found based on the validated mathematical models.
STEEL RESEARCH INTERNATIONAL
(2023)
Article
Chemistry, Physical
Wenke Wang, Xinhua Liu, Zhihao Wang, Miaomiao Chen, Wenzhen Chen, Wencong Zhang, Hyoung Seop Kim
Summary: This study investigates the effects of asymmetric basal texture on the stretchability and microstructure variations of magnesium alloy sheet. The results show that plastic deformation is concentrated in the central region of the sample during stretch forming, and the transverse direction sample has higher stretch formability. This is attributed to the weak basal texture in the transverse direction sample, which activates more basal slip and tension twinning. Additionally, the activation of basal slip narrows the spread angle of the basal pole for the transverse direction sample, while only increasing the basal texture intensity for the rolling direction sample.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Jiajia Shen, Rita Goncalves, Yeon Taek Choi, J. G. Lopes, Jin Yang, N. Schell, Hyoung Seop Kim, J. P. Oliveira
Summary: This study establishes a correlation between welding process, microstructure, and mechanical properties, laying the foundations for the successful joining and application of welded joints based on high entropy alloys using low-cost arc-based welding technologies.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Farahnaz Haftlang, Jae Bok Seol, Alireza Zargaran, Jongun Moon, Hyoung Seop Kim
Summary: Maraging structural materials have been used for centuries, but their low ductility has limited their application. In this study, a dual-phase medium-entropy Fe68Ni10Mn10Co10Ti1.5Si0.5 maraging alloy with high strength (1.6 GPa) and enhanced ductility (-25%) is developed by injecting metastable austenite into the microstructure. The combination of metastability and heterogeneity achieved through heat treatment techniques can provide a breakthrough in developing maraging materials with large ductility.
Article
Chemistry, Physical
Soung Yeoul Ahn, Dong Geun Kim, Jeong Ah Lee, Eun Seong Kim, Sang Guk Jeong, Rae Eon Kim, Jungho Choe, Soon-Jik Hong, Pham Quang, Sunghak Lee, Hyoung Seop Kim
Summary: This study investigates the mechanical properties of CoCrFeMnNi high-entropy alloy (HEA) manufactured through direct energy deposition. The effect of strain rate on the mechanical properties was analyzed, and a Johnson-Cook constitutive model was employed for simulation. The results showed that the microstructural behavior of the HEA was influenced by strain localization and twin formation, which have significant implications for the design and development of HEAs under extreme environments.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Soung Yeoul Ahn, Farahnaz Haftlang, Eun Seong Kim, Sang Guk Jeong, Ji Sun Lee, Hyoung Seop Kim
Summary: Reinforcement by composite fabrication has been studied to improve the strength of high-entropy alloys (HEAs). In this study, CoCrFeMnNi+B4C high-entropy composite (HEC) parts were fabricated using the direct energy deposition process. The presence of B4C nano-particles hindered grain growth and caused elemental segregation, leading to the formation of carbide-rich regions. The B4C nano-particles also promoted the pinning effect of dislocations and provided dispersion hardening, resulting in high mechanical strength of the CoCrFeMnNi+B4C HEC.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Selim Kim, Dong Geun Kim, Minu Kim, Ki Jong Kim, Jae Min Lee, Joon Hyuk Lee, Hae-Won Cheong, Hyoung Seop Kim, Sunghak Lee
Summary: Various Al foams have been developed to meet the increasing demands for impact reduction in military, automotive, civil-engineering, and aerospace applications. Evaluating their energy-absorbing performance is challenging due to the rapid closure of interior pores. This study modified a split Hopkinson pressure bar (SHPB) to reliably evaluate the energy-absorbing performance of open- and closed-cell Al foams using the incident wave alone.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Jungwan Lee, Sujung Son, Seok Su Sohn, Jae Wung Bae, Hyoung Seop Kim
Summary: Hot rolling induces dynamic recrystallization and dislocation-based microbands in metastable medium-entropy alloys, leading to deformation-induced martensitic transformation at ambient temperature. This phenomenon is not identifiable in the as-annealed counterparts. As a result, the as-hot-rolled states of these alloys exhibit approximately 43% total elongation and doubled yield strength.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
Selim Kim, Hyungu Kang, Minu Kim, Ki Jong Kim, Jae Min Lee, Hae-Won Cheong, Hyoung Seop Kim, Sunghak Lee
Summary: This study suggests that stacks of thin aluminum sheets with fine rectangular or triangular grooves are effective materials for energy absorption. The energy-absorbing performance of these materials was evaluated using a modified split Hopkinson pressure bar (SHPB). The study found that the grooves shape, groove cavity fraction, and specimen thickness affect the energy-absorbing parameters, including impact momentum and maximum impact acceleration. Both impact momentum and maximum impact acceleration showed a continuous decrease as the specimen thickness increased or as the groove cavity fraction increased. The triangular grooved specimens exhibited greater reduction in impact momentum compared to the rectangular grooved specimens. The overall energy-absorbing performance of the triangular grooved specimens was better than that of the rectangular grooved specimens. Notably, in the triangular grooved specimens with a high cavity fraction, the triangular embossing intruded into the groove cavities, resembling a 'zipper' mechanism, further enhancing the effectiveness of energy absorption. This study presents a promising approach for developing grooved aluminum sheet stacks with reduced impact momentum and maximum impact acceleration by exploring suitable groove shapes, cavity fractions, and stack thicknesses, especially in dynamically compressed artillery environments.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
Rae Eon Kim, Sang Guk Jeong, Hyojeong Ha, Do Won Lee, Auezhan Amanov, Hyoung Seop Kim
Summary: Metal additive manufacturing (MAM) is capable of designing complex geometries with optimized and near-net-shaped structures. However, defects generated during the manufacturing process have limited its industrial applications. This study proposes a new strategy using ultrasonic nanocrystal surface modification (UNSM) to reduce defects and improve the mechanical properties of MAM parts.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
Rae Eon Kim, Gang Hee Gu, Yeon Taek Choi, Jeong Ah Lee, Hyoung Seop Kim
Summary: Heterostructuring is a method for achieving a combination of strength and ductility, but its usage is limited due to poor formability. In this study, a new strategy for designing heterostructures optimized for non-uniform deformation is proposed. The fabricated inverse-gradient structure of cold-rolled CoCrFeMnNi high-entropy alloy sheets exhibited superior strength-ductility synergy and excellent bendability. This is attributed to the prevention of external cracks and reduced damage evolution caused by the inverse-gradient structure. Overall, the heterostructured high-entropy alloys demonstrated superior tensile properties and formability.
SCRIPTA MATERIALIA
(2023)
Article
Nanoscience & Nanotechnology
Shiyu Du, Tuanwei Zhang, Zhiming Jiao, Dan Zhao, Jianjun Wang, Renlong Xiong, Hyoung Seop Kim, Zhihua Wang
Summary: A novel strategy of designing analogous harmonic structures (AHS) is implemented to enhance the strength-ductility synergy in the Co-Cr-Ni-based medium-entropy alloy (MEA). The AHS-MEA achieves high yield strength of 1028 MPa, ultimate tensile strength of 1558 MPa, and considerable uniform elongation of 20%. The study provides new insights into the nanocrystalline formation mechanism and excellent strength-ductility synergy.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Sujung Son, Jungwan Lee, Peyman Asghari-Rad, Rae Eon Kim, Hyojin Park, Jae-il Jang, Wen Chen, Yoon-Uk Heo, Hyoung Seop Kim
Summary: This study successfully synthesized a hierarchically heterogeneous microstructure by combining eutectic high-entropy alloy and medium-entropy alloy powders through powder metallurgy-based severe plastic deformation method, achieving strong hetero-deformation-induced strengthening effect. This is of great significance for the development of HEAs.
MATERIALS RESEARCH LETTERS
(2023)
Article
Engineering, Manufacturing
Anatoliy Zavdoveev, Andrey Klapatyuk, Thierry Baudin, Eric MacDonald, Dhanesh Mohan, J. P. Oliveira, Alex Gajvoronskiy, Valeriy Poznyakov, Hyoung Seop Kim, Francois Brisset, Maksym Khokhlov, Mark Heaton, Massimo Rogante, Mykola Skoryk, Dmitry Vedel, Roman Kozin, Illya Klochkov, Sviatoslav Motrunich
Summary: This study proposes the wire arc additive manufacturing method for non-equimolar Co-Cr-Fe-Mn-Ni high-entropy alloy using gas metal arc welding (GMAW) with metal powder-cored wire (MPCW). The filler powder contains Co-Cr-Mn-Ni components in equal atomic amounts relative to each other with Fe metal stripe as a shield. This method allows for building high-entropy alloy samples with desired characteristics. It outperforms alternative methods such as vacuum melting, plasma arc melting, selective laser melting, or electron beam melting in multiple indicators.
ADDITIVE MANUFACTURING LETTERS
(2023)