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Tae-Hyuk Lee Young-Jun Lee Dong-Jae Park Jae-Soo Noh Chan-Hyun Park 《Journal of Nuclear Science and Technology》2013,50(12):1490-1495
The main goal of this research was to investigate the relationship between the grain boundary misorientation and the precipitation of intergranular M23C6 carbides during the pilgering process and the heat treatment of Inconel 690 tubes for steam generators. The M23C6 carbides behavior is obviously influenced by the grain boundary character and interfacial energy. The grain boundary misorientation of the Inconel 690 tubes was investigated by electron backscattered diffraction of carbide precipitates at these grain boundaries. Numerous M23C6 carbide precipitate at the large angle grain boundaries with high interfacial energy. 相似文献
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Jeoung Hyeong-Jun Kim Youngjae Lee Tae-Hyuk Lee Jin-Young Kim Young Min Yi Kyung-Woo Kang Jungshin 《Journal of Applied Electrochemistry》2022,52(10):1535-1549
Journal of Applied Electrochemistry - An environmentally friendly and effective molten salt electrolysis process using a copper (Cu) cathode was developed for producing magnesium (Mg) metal from... 相似文献
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Tae-Hyuk Lee Ju-Hyeon Sun H.H. Nersisyan Ha-Guk Jung Kap-Ho Lee Jong-Hyeon Lee 《Composites Part A》2012,43(9):1490-1496
A combination of combustion synthesis (CS) and spark plasma sintering (SPS) technology was employed in the fabrication of Al/AlN/CuAl2 dense composites. Al/AlN/CuAl2 composite powders in which a portion of the AlN was present in macro- and nanofiber forms were prepared by combustion of Al–Cu–5 wt.% (C2F4)n, under a nitrogen atmosphere. The resulting composite powders were then subjected to consolidation by SPS at a dwell temperature level of 1500 °C, mechanical pressure of 60 MPa, and a non-isothermal heating time of 10 min. It is found that the actual thermal conductivity of Al/AlN/CuAl2 composites fabricated with 5 wt.% (C2F4)n is much higher than that of materials prepared in the absence (C2F4)n. Maximum thermal conductivity (320 W/m K) was recorded for the samples prepared from an 0.8Al–0.2Cu–5 wt.% (C2F4)n mixture. The influence of (C2F4)n on the growth mechanism of AlN fibers and thermal conductivity of composite samples is discussed in light of the experimental data. 相似文献
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ABSTRACT The effect of solution annealing and aging treatment on the intergranular carbide precipitation behavior of alloy 690 tubes for steam generators is investigated. The carbides precipitated on the grain boundaries were identified as chromium-rich M23C6 carbide, which has a cube-cube orientation relationship with the matrix on one side of neighboring grains. The carbide precipitation behavior is closely related to the interaction between the solubility of carbon in Ni-based matrix and diffusion of alloying elements. The ultimate tensile strength and elongation of the solution annealed alloy 690 tubes at 300°C are 638.8 ± 12.4 MPa and 43.2 ± 4.2%, respectively. In the early stage of precipitation, the ultimate tensile strength increased to 720.4 ± 13.5 MPa. The carbides function as reinforcement in alloy 690 and provide strength enhancement with aging time reached 15 hours. However, when the aging time passed 15 hours, this property gradually decreased to 710.6 ± 12.6 MPa due to the low bonding strength between the carbide and matrix. 相似文献
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Basit Ali Sang-Hoon Choi So-Yeon Kim Jae-Jin Sim Sang-Hyun Lee Seok-Jun Seo Taek-Soo Kim Dae-Guen Kim Kyoung-Mook Lim Tae-Hyuk Lee Kyoung-Tae Park 《Metals and Materials International》2016,22(6):1073-1082
In this study, Fe-based powder of composition Fe-3 wt% Cr-0.5 wt% Mo was prepared using a water atomization process. After atomization, the total oxide content of the powder was calculated as ca. 2.09 wt%. Gas reduction of the as-atomized powder using CO, CH4, and H2 gases was carried out in a horizontal vacuum tubetype furnace at 900 °C. Thermodynamic and kinetic calculations for the reduction reactions were carried out using FactSage and HSC Chemistry programs. The results showed that the reduction proceeded in two stages: from Fe3O4 to FeO, and finally to Fe. Each reducing gas was evaluated and compared based on the oxide reduction capability. The lowest oxygen content was achieved for CH4 (0.49 wt%). However, with CH4, cementite (Fe3C) was also detected due to cracking of CH4. 相似文献
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Jong-Youl Park Tae-Hyung Na Tae-Hyuk Lee Bo-Young Lee Jae-Sung Kim 《Journal of Nuclear Science and Technology》2013,50(5):748-757
The welding of zirconium alloy components is one of the most critical processes in the fabrication of nuclear fuel rods used in pressurized water reactors. For this, various welding processes, such as gas tungsten arc welding, electron beam welding, laser beam welding, and resistance pressure welding (RPW), are used around the world. In Korea, the RPW process is being used to fabricate nuclear fuel assembly fuel rods. This study investigated changes in the weldment shape owing to welding conditions such as welding current, welding force, and overlapping. The welding soundness of the weldment was evaluated by hydraulic burst test. The welding temperature of the weld zone was measured using a thermal infrared method. Discontinuous black spots in the weld line, regarded as a non-bonding defect, were confirmed as spots caused by the carbide precipitation of zirconium during welding. 相似文献
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Junhee Kim Soonyoung Choi Jinsu Baek Yong Il Park Jin Chul Kim Ji-Eun Jeong Hyocheol Jung Tae-Hyuk Kwon Byeong-Su Kim Sang-Ho Lee 《Advanced functional materials》2023,33(33):2370198
Topology control of polymers is critical for determining their physical properties and potential applications; in particular, topologies that incorporate numerous hydrogen bonding (H-bonding) donors and acceptors along the polymer chains considerably influence the formation of different inter- and intramolecular H-bonding motifs. In this study, the high-level control of inter- and intramolecular H-bonding is investigated in topology-controlled poly(glycidoxy carbonyl benzoic acid)s (PGCs). Three types of topology-controlled PGCs (i.e., linear, hyperbranched, and branched cyclic structures having a similar degree of polymerization) are prepared by introducing aromatic carboxylic acids into the corresponding polyglycidols (PGs) via quantitative post-polymerization modification with phthalic anhydride. The obtained three types of PGCs demonstrated the high-level interplay between the inter- and intramolecular H-bonding in polymer chains by exhibiting the pH-dependent self-association properties in the solution state and the strong adhesion properties in the bulk state with high transparency. Interestingly, the dramatically enhanced adhesive property by 2.6-fold is demonstrated by simple mixing of branched cyclic PGC and topology-controlled PGs to promote the cooperative H-bonding between polymer chains. The new class of cooperative H-bonding is anticipated between topology-controlled polymers to contribute to the development of advanced adhesive and the high potential in biological and biomedical applications due to its excellent biocompatibility. 相似文献
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