• Title/Summary/Keyword: advanced materials

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Evaluation of Mechanical Properties and Microstructure Depending on Sintering Heating Rate of IN 939 W Alloy (IN 939 W 합금의 소결 승온 속도에 따른 물리적 특성과 미세조직 분석)

  • Jeon, Junhyub;Lee, Junho;Seo, Namhyuk;Son, Seung Bae;Jung, Jae-Gil;Lee, Seok-Jae
    • Journal of Powder Materials
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    • v.29 no.5
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    • pp.399-410
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    • 2022

  • Changes in the mechanical properties and microstructure of an IN 939 W alloy according to the sintering heating rate were evaluated. IN 939 W alloy samples were fabricated by spark plasma sintering. The phase fraction, number density, and mean radius of the IN 939 W alloy were calculated using a thermodynamic calculation. A universal testing machine and micro-Vickers hardness tester were employed to confirm the mechanical properties of the IN 939 W alloy. X-ray diffraction, optical microscopy, field-emission scanning electron microscopy, Cs-corrected-field emission transmission electron microscopy, and energy dispersive X-ray spectrometry were used to evaluate the microstructure of the alloy. The rapid sintering heating rate resulted in a slightly dispersed γ' phase and chromium oxide. It also suppressed the precipitation of the η phase. These helped to reinforce the mechanical properties.

  • https://doi.org/10.4150/KPMI.2022.29.5.399 인용 PDF KSCI

Austenite Stability of Sintered Fe-based Alloy (철계 소결합금의 오스테나이트 안정성)

  • Choi, Seunggyu;Seo, Namhyuk;Jun, Junhyub;Son, Seung Bae;Lee, Seok-Jae
    • Journal of Powder Materials
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    • v.27 no.5
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    • pp.414-419
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    • 2020

  • In the present study, we investigated the austenite stability of a sintered Fe-based nanocrystalline alloy. The volume fraction of austenite was measured based on the X-ray diffraction data of sintered Fe-based nanocrystalline alloys, which were prepared by high-energy ball milling and spark plasma sintering. The sintered alloy samples showed a higher volume fraction of austenite at room temperature as compared to the equilibrium volume fraction of austenite obtained using thermodynamic calculations, which resulted from the nanosized crystalline structure of the sintered alloy. It was proved that the austenite stability of the sintered Fe-based alloy increased with a rise in the amount of austenite stabilizing elements such as Mn, Ni, and C; however, it increased more effectively with a decrease in the actual grain size. Furthermore, we proposed a new equation to predict the martensite starting temperature for sintered Fe-based alloys.

  • https://doi.org/10.4150/KPMI.2020.27.5.414 인용 PDF KSCI

A flexible OTFT-OLED display using solution-processed organic dielectrics

  • Hirai, Nobukazu;Katsuhara, Mao;Yagi, Iwao;Yasuda, Ryoichi;Ushikura, Shin-Ich;Noda, Makoto;Moriwaki, Toshiki;Imaoka, Ayaka;Yoneya, Nobuhide;Yumoto, Akira;Nomoto, Kazumasa;Urabe, Tetsuo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.131-134
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    • 2009

  • We have developed a flexible OTFT backplane in which all the dielectrics are formed by solutionprocess in order to achieve low-cost and highthroughput manufacturing. The backplane successfully drives a flexible AM-OLED display with peak brightness of > 200 nit and the contrast ratio of > 1000:1 with great mechanical flexibility.

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