Updated on 2023/11/11

写真a

 
YOON Sungmin
 
Organization
Graduate School of Engineering Micro-Nano Mechanical Science and Engineering 1 Designated assistant professor
Title
Designated assistant professor
External link

Degree 1

  1. Doctor of Engineering ( 2022.3   Nagoya University ) 

Research Interests 4

  1. Fractography

  2. Mechanics of Materials

  3. Engineering materials

  4. Microstructure observation

Research Areas 1

  1. Nanotechnology/Materials / Material processing and microstructure control

Education 1

  1. Nagoya University   Micro-Nano Mechanical Science and Engineering   Doctor of Engineering

    - 2022.3

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    Country: Japan

Professional Memberships 1

  1. The Japan Society of Mechanical Engineers

 

Papers 16

  1. High Temperature Tensile and Compressive Behaviors of Nanostructured Polycrystalline AlCoCrFeNi High Entropy Alloy: A Molecular Dynamics Study

    Sungmin Yoon, Yasuhiro Kimura, Motoki Uchida, Yang Ju, Yuhki Toku

    Journal of Engineering Materials and Technology-Transactions of the ASME   Vol. 146 ( 2 )   2023.10

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    Publishing type:Research paper (scientific journal)   Publisher:ASME International  

    Abstract

    Molecular dynamics studies were performed to assess tensile and compressive behaviors at high temperatures up to 1200 °C for nanostructured polycrystalline AlCoCrFeNi high entropy alloy (HEA). As the temperature increased, the tensile yield stress, tensile/compressive ultimate strengths, and elastic modulus decreased, whereas the compressive yield stress remained constant. The temperature dependence of the phase structures (face-centered cubic (FCC) and hexagonal close-packed (HCP)) showed notable features between tension and compression. The HEA underwent FCC → HCP phase transformation when strained under both tension and compression. The evolution of the intrinsic stacking faults (ISFs) and extrinsic stacking faults (ESFs), which underwent FCC → HCP phase transformation, was observed. During compression, the ISFs → ESFs transition produced parallel twins. The evolution of mean dislocation length for the perfect, Shockley, and stair-rod partial dislocations was observed. Changes in the Shockley and stair-rod partial dislocations were observed after experiencing strain. The temperature dependence of the Shockley partial dislocation was high, whereas the stair-rod partial dislocation exhibited low-temperature dependence. From the simulation results, the structural usage of nanostructured polycrystalline AlCoCrFeNi HEA at elevated temperatures is recommended.

    DOI: 10.1115/1.4063802

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  2. Overcoming the trade-off between strength and ductility in austenitic stainless steel using a high-density pulsed electric current

    Sungmin Yoon, Yasuhiro Kimura, Yuhki Toku, Yang Ju

    Materialia     page: 101922 - 101922   2023.10

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.mtla.2023.101922

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  3. Thermal stress-assisted formation of submicron pillars from a thin film of CoCrCuFeNi high entropy alloy: experiments and simulations

    Yoon Sungmin, Kimura Yasuhiro, Gu Shaojie, Toku Yuhki, Ju Yang, Cui Yi

    RSC ADVANCES   Vol. 13 ( 41 ) page: 28513 - 28526   2023.9

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  4. Annealing Effect of High-Density Pulsed Electric Current Treatment on Cold-Rolled 6061 Aluminum Alloy

    Yu Xiaoming, Gu Shaojie, Yoon Sungmin, Kimura Yasuhiro, Toku Yuhki, Ju Yang

    Journal of Materials Engineering and Performance     2023.9

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media {LLC}  

    DOI: 10.1007/s11665-023-08522-z

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  5. Realizing strength–ductility synergy in a lean duplex stainless steel through enhanced TRIP effect via pulsed electric current treatment

    Gu S., Liu C., Kimura Y., Yoon S., Cui Y., Yan X., Ju Y., Toku Y.

    Materials Science and Engineering: A   Vol. 883   2023.9

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    Publisher:Materials Science and Engineering: A  

    Optimization of the strength–ductility compromise in lean duplex stainless steels (LDSSs) often involves controlling the stability of austenite by chemically adjusting it to be metastable and enabling phase transformation through a transformation-induced plasticity (TRIP) effect during plastic deformation. This study investigated the effects of pulsed electric current (PEC) treatment on the spatial distribution of alloying elements within the microstructure and enhancement of the mechanical properties of a new type of LDSS material, NSSC2120. The results showed that PEC treatment had a significant positive impact on the mechanical properties of NSSC2120. Specifically, after applying 20 pulses of PEC treatment at a current density of 700 A/mm2 for 8 ms, the material exhibited a 27% increase in ductility and 8% increase in strength. The microstructural evolution induced by the PEC treatments was investigated using quasi-in-situ electron backscatter diffraction and energy-dispersive X-ray spectroscopy. The PEC treatment facilitated the diffusion of alloying elements, which played a crucial role in triggering the TRIP effect during plastic deformation owing to the decreased stability of austenite with a lower content of austenite-stabilizing elements, thereby resulting in simultaneous improvement in both strength and ductility. Significantly, the rapid thermal process employed in the PEC treatment did not give rise to detrimental precipitates within the microstructure of the material, rendering PEC treatment a promising alternative to conventional heat treatment. The simplicity, speed, and low energy consumption associated with the PEC treatment make it an appealing choice for processing similar materials and achieving both microstructural modification and optimization of mechanical properties.

    DOI: 10.1016/j.msea.2023.145534

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  6. Effect of high-density pulsed electric current on residual stress relief and microstructural modification of cold-bent commercially pure titanium

    Shaoli Li, Shaojie Gu, Sungmin Yoon, Yasuhiro Kimura, Yuhki Toku, Bin Liu, Yang Ju

    Materials Today Communications     2023.9

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.mtcomm.2023.107082

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  7. Effect of high-density pulsed electric current on the formability of aluminum alloy

    Jung Jaewoong, Gu Shaojie, Yoon Sungmin, Kimura Yasuhiro, Toku Yuhki, Ju Yang

    INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY   Vol. 128 ( 3-4 ) page: 1505 - 1515   2023.9

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    Publisher:International Journal of Advanced Manufacturing Technology  

    In this study, an energy-saving and highly efficient high-density pulsed electric current (HDPEC) method was used to improve the formability of the aluminum alloy A6061 after T6 heat treatment (A6061-T6). An interrupted tensile test was performed, and the HDPEC treatment was applied after tensile deformation. The results showed that the ductility of A6061-T6 improved by approximately 33% after three HDPEC treatments. The Vickers hardness and residual stress were measured to investigate the effect of the pulsed electric current on formability, and they were recovered after HDPEC treatment. Furthermore, the microstructural morphology and dislocation density were investigated to understand the mechanism of formability enhancement. Detailed analysis shows that the formability enhancement of A6061-T6 after HDPEC treatment is mainly attributed to dislocation elimination, while grain size and crystalline orientation changes are side effects. In addition, the results of equivalent heat treatments demonstrate that the athermal effect of the HDPEC treatment plays a crucial role in the removal of dislocations. Thus, due to the contribution of the athermal effect, HDPEC treatment realizes the advantages of low consumption and high efficiency, and can be dedicated to green processing and manufacturing of metallic materials.

    DOI: 10.1007/s00170-023-11841-z

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  8. Rapid microstructure modification of laser powder-bed fused superalloy IN718 using high-density pulsed electric current

    Liu C., Gu S., Yan X., Yoon S., Kimura Y., Toku Y., Ju Y.

    Materials Today Communications   Vol. 36   2023.8

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    Publisher:Materials Today Communications  

    A novel high-density pulsed electric current (HDPEC) method is developed to modify the grain-scale microstructure of laser powder-bed fused Ni-based superalloy IN718, which has not been reported in other studies. Rapid micro-residual stress relief and micro-segregation alleviation were achieved without significant grain coarsening which is common in conventional heat treatment. This technique can be an alternative energy-saving post-treatment method for additively manufactured metallic materials, enabling rapid and efficient annealing and solution treatment.

    DOI: 10.1016/j.mtcomm.2023.106892

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  9. Influence of a high-density pulsed electric current on the fatigue behaviour of prestrained aluminium alloys

    Jung Jaewoong, Yoon Sungmin, Gu Shaojie, Kimura Yasuhiro, Toku Yuhki, Ju Yang

    ENGINEERING FAILURE ANALYSIS   Vol. 150   2023.8

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    Publisher:Engineering Failure Analysis  

    This study quantitatively analysed the effect of an electric current on improving the fatigue life of the aluminium alloy A6061-T6. The effect of a high-density pulsed electric current (HDPEC) was investigated for non-prestrained and prestrained aluminium alloys because they are frequently exposed to plastic deformation. The results showed that the HDPEC contributed to increasing the fatigue life of both materials with and without prestrain, and those without prestrain increased significantly with the HDPEC effect. Local melting sites were observed at the fatigue crack tip on the fracture surface of the non-prestrained and prestrained cases treated with HDPEC. Fatigue crack growth tests confirmed the improved fatigue life of the HDPEC effect. The results pave the way toward enhancing the resistance of fatigue crack growth in welded joints.

    DOI: 10.1016/j.engfailanal.2023.107230

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  10. Efficiency improvement of fatigue crack healing by multiple high-density pulsed electric currents: Application to austenitic stainless steel

    Yoon Sungmin, Gu Shaojie, Li Shaoli, Kimura Yasuhiro, Toku Yuhki, Ju Yang

    ENGINEERING FRACTURE MECHANICS   Vol. 284   2023.5

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    Publisher:Engineering Fracture Mechanics  

    This study aims to demonstrate the use of a novel treatment approach for fatigue crack healing. High-density pulsed electric currents, which have been widely used for fatigue crack healing of metals, can exert synergistic effects on fatigue crack healing by both compressive stress (owing to the Joule heating) and dislocation motion (owing to the electron wind force). However, these synergistic effects are sometimes weakened by temperature elevations owing to high current densities, failing to efficiently heal fatigue cracks owing to the thermal degradation of metals. In this study, type 316 austenitic stainless steel, which is the most common metallic material, was considered for investigating fatigue crack healing improvement under controlled crack tip temperature elevation owing to the Joule heating induced by multiple high-density pulsed electric currents. Appropriate current parameters such as current density and pulse number under fixed pulse duration were optimized. The results revealed microstructural modifications, such as crack closure with crack bridging, annihilation of slip bands, and material filling near the crack tips, which is promising for fatigue crack healing improvement. The results of fatigue crack growth tests validated these microstructure improvements.

    DOI: 10.1016/j.engfracmech.2023.109235

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  11. Rapid anisotropy recovery in deformed FCC metals by high-density pulsed electric current treatment Reviewed

    Shaojie Gu, Yi Cui, Sungmin Yoon , Zizheng Wang , Yasuhiro Kimura , Yuhki Toku , Yang Ju

    Vacuum   Vol. 197 ( 110855 ) page: 1 - 5   2022.3

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.1016/j.vacuum.2021.110855

    DOI: https://doi.org/10.1016/j.vacuum.2021.110855

  12. Improvement of low-cycle fatigue life of austenitic stainless steel by multiple high-density pulsed electric currents Reviewed

    Sungmin Yoon, Yi Cui, Yasuhiro Kimura, Shaojie Gu, Yuhki Toku, Yang Ju

    International Journal of Fatigue   Vol. 156 ( 106639 ) page: 1 - 9   2022.3

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.1016/j.ijfatigue.2021.106639

    DOI: https://doi.org/10.1016/j.ijfatigue.2021.106639

  13. Rapid anisotropy recovery in deformed FCC metals by high-density pulsed electric current treatment

    Gu S., Cui Y., Yoon S., Wang Z., Kimura Y., Toku Y., Ju Y.

    Vacuum   Vol. 197   2022.3

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    Publisher:Vacuum  

    The {101} texture of deformed face-centered cubic metals, such as 316 stainless steel and Ni-based alloy Inconel 718, was successfully alleviated by high-density pulsed electric current (HDPEC) treatment. Furthermore, the deformed grains recovered after the HDPEC treatment. The HDPEC induced the rapid dislocation motion and grain refinement that resulted in random grain orientation and equiaxed grain morphology, which led to anisotropy recovery in the deformed metals. This method provides a promising way to modify the microstructure of materials with short time and low cost, after forming or during service.

    DOI: 10.1016/j.vacuum.2021.110855

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  14. Improvement of low-cycle fatigue life of austenitic stainless steel by multiple high-density pulsed electric currents

    Yoon Sungmin, Cui Yi, Kimura Yasuhiro, Gu Shaojie, Toku Yuhki, Ju Yang

    INTERNATIONAL JOURNAL OF FATIGUE   Vol. 156   2022.3

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    Publisher:International Journal of Fatigue  

    This study evaluated the low-cycle fatigue (LCF) life of type 316 austenitic stainless steel to determine the effect of multiple high-density pulsed electric currents (HDPECs). Fatigue properties were analyzed with the fatigue crack growth (FCG) and LCF tests by considering different conditions of multiple HDPECs and its application. The HDPEC densities of 100, 150 and 200 A/mm2 with application numbers from 1 to 17 times were used. The LCF results were assessed by using fatigue models, and the effectiveness of the application methods was examined. Under the HDPEC density of 200 A/mm2, increasing the number of HDPECs during the period of crack propagation is the best way for delaying FCG. Multiple applications of HDPEC caused a decrease in the length and an increase in the depth of striations in the specimen's fatigue fracture surface, and the degree of ductility was increased thereby leading to the delay in FCG. The proposed conditions pave the way toward improving the LCF life of the material.

    DOI: 10.1016/j.ijfatigue.2021.106639

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  15. Assessment of creep behavior using a damage-coupled model for martensitic stainless steel Reviewed International coauthorship

    Sungmin YOON, Yasuhiro KIMURA, Yuhki TOKU, Yang JU, Yunhae KIM

    JSME Mechanical Engineering Journal   Vol. 8 ( 5 ) page: 1 - 11   2021.8

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.1299/mej.21-00178

    DOI: https://doi.org/10.1299/mej.21-00178

  16. Evaluation of Electric Current-Induced Improvement of Fracture Characteristics in SUS316 Reviewed

    Sungmin Yoon, Yasuhiro Kimura, Yi Cui, Yuhki Toku, Yang Ju

    Materials Transactions   Vol. 62 ( 6 ) page: 748 - 755   2021.4

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.2320/matertrans.MT-M2020333

    DOI: https://doi.org/10.2320/matertrans.MT-M2020333

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Presentations 3

  1. 分子動力学シミュレーションによるAlCoCrFeNi高エントロピー合金の高温引張圧縮特性の解析

    日本機械学会、M&M・CMD 若手シンポジウム 2023  2023.8.7 

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    Event date: 2023.8

    Venue:金沢  

  2. Fatigue damage recovery of austenitic stainless steel by high-density pulsed electric current

    Sungmin YOON,Yang JU, Yasuhiro KIMURA, Yuhki TOKU

    ⽇本⾦属学会2021年秋期(第169回)  2021.9.16 

  3. Fabrication of small-scale CoCrCuFeNi high entropy alloy pillars by Hillock growth

    Sungmin YOON, Yi CUI, Yasuhiro KIMURA, Yuhki TOKU, Shaojie GU and Yang JU

    日本機械学会 M&M2022 材料力学カンファレンス, 弘前大学  2022.9.27 

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    Language:English  

KAKENHI (Grants-in-Aid for Scientific Research) 1

  1. Tensile and Fatigue Properties of CoCrFeNi-Based High Entropy Alloys by Current Application of High-Density Pulsed Electric Cureent

    2023.4 - 2025.3

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    Authorship:Principal investigator