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Abstract

Ice formed on radome surfaces causes communication disruption due to radio-frequency interference (RFI), which reveals the importance of de-icing systems for radomes. As a radome de-icing application, in this work, carbon nanotube (CNT) thin films were fabricated using a spray-coating method, and influence of process parameters on RF transmittance and electrothermal properties was investigated. With the increase of spraying time, sheet resistance of the fabricated film decreases, which results in a decrease of the RF transmittance and improvement of the heating performance. Also, the de-icing capability of the fabricated CNT film was evaluated at –20oC, and efficient removal of ice under cold conditions was demonstrated.

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Authors and Affiliations

Jun Hyuk Jung
Jiwon Hong
Youngryeul Kim
Seok-Min Yong
Jinwoo Park
Seung Jun Lee
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Abstract

Fusion welding of Ti-Cu is difficult because of big difference of melting points and formation of brittle intermetallic compounds. Friction stir welding is carried out by solid-state joining, thermo-mechanical stirring, and friction heat. Ti-Cu FSW dissimilar welding can supply a very sound joint area with a few intermetallic compounds. Optimized welding process conditions are essential to obtain suitable microstructure and mechanical properties of welded zones. Different welding speeds affect the evolution of microstructure and mechanical properties due to changes of input heat and internal stored deformation energy. The correlation of microstructure and mechanical properties of Ti-Cu welded zone according to welding speeds were investigated and analyzed. As the higher the welding speed, the lower the heat input and the lower the temperature rise. Ti-Cu 75 has the smallest grain size at 13.9 μm, but the optimum mechanical properties and the integrity of welding were shown in Ti-Cu 50.
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Authors and Affiliations

Yong-Jae Lee
1
ORCID: ORCID
Won-Ki Jeong
1
Seung-Jun Lee
2
Hidetoshi Fujii
3
Se Eun Shin
1
Dong-Geun Lee
1
ORCID: ORCID

  1. Sunchon National University, Department of Materials Science and Metallurgical Engineering, Suncheon, 57922, Republic of Korea
  2. Korea Polytechnic University, Department of Advanced Materials Engineering, Siheung, 15073, Republic of Korea
  3. Osaka University, Joining and Welding Research Institute, Osaka 567-0047, Japan
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Abstract

In this study, stainless steel 316L and Inconel 625 alloy powders were additively manufactured by using directed energy deposition process. And heat treatment effect on hardness and microstructures of the bonded stainless steel 316L/Inconel 625 sample was investigated. The microstructures shows there are no secondary phases and big inclusions near interfacial region between stainless steel 316L and Inconel 625 except several small cracks. The results of TEM and Vickers Hardness show the interfacial area have a few tens of micrometers in thickness. Interestingly, as the heat treatment temperature increases, the cracks in the stainless steel region does not change in morphology while both hardness values of stainless steel 316L and Inconel 625 decrease. These results can be used for designing pipes and valves with surface treatment of Inconel material based on stainless steel 316L material using the directed energy deposition.
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Bibliography

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[2] A. Ambrosi, M. Pumera, Chem. Soc. Rev. 45, 2740 (2016).
[3] G .S. Lee, Y.S. Eom, K.T. Kim, B.K. Kim, J. H. Yu, J. Korean Powder Metall. Inst. 26, 138 (2019).
[4] Y.S. Eom, D.W. Kim, K.T. Kim, S.S. Yang, J. Choe, I. Son, J.H. Yu, J. Korean Powder Metall. Inst. 27, 103 (2020).
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[9] R . Koike, I. Unotoro, Y. Kakinuma, Y. Oda, Int. J. Autom. Techno. 13, 3 (2019).
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Authors and Affiliations

Yeong Seong Eom
1 2
Kyung Tae Kim
1
Dong Won Kim
1
Ji Hun Yu
1
Chul Yong Sim
3
Seung Jun An
3
Yong-Ha Park
4
Injoon Son
2
ORCID: ORCID

  1. Korea Institute of Materials Science, 797 Changwon-daero, Changwon, Republic of Korea
  2. Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, Republic of Korea
  3. Insstek, Daejeon, Republic of Korea
  4. Samsung Heavy Industries, Geoje-si, Republic of Korea

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