• Title/Summary/Keyword: ATJ 흑연

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Compression Fracture Behavior of ATJ Graphite for Rocket Nozzle throat (로켓 노즐목에 사용하는 ATJ 흑연의 압축 파단 특성)

  • Choi, Hoonseok;Kim, Jaehoon;Kim, Yeonwook;Seo, Bohwi;Moon, Soonil
    • Journal of the Korean Society of Propulsion Engineers
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    • v.18 no.4
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    • pp.61-66
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    • 2014
  • Graphite is commonly used for rocket nozzle. The purpose of the present study is to evaluate compression fracture behavior of ATJ graphite. Uniaxial compression test is conducted in accordance with ASTM C 695 in the range of R.T to $900^{\circ}C$. The size effects of specimen on the compressive strength and fracture behavior were investigated. Two types of cylindrical specimen, i.e., where the diameter to length ratio is 1:2 (ASTM C 695 specimen) or 1:1, were tested at room temperature.

Fracture Behavior of Graphite Material at Elevated Temperatures Considering Oxidation Condition (산화환경을 고려한 흑연 내열재의 고온파단특성)

  • Choi, Hoon Seok;Kim, Jae Hoon;Oh, Kawng Keun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.11
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    • pp.1091-1097
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    • 2015
  • Graphite material has been widely used for making the rocket nozzle throat because of its excellent thermal properties. However, when compared with typical structural materials, graphite is relatively weak with respect to both strength and toughness, owing to its quasi-brittle behavior, and gets oxidized at $450^{\circ}C$. Therefore, it is important to evaluate the thermal and mechanical properties of this material for using it in structural applications. This study presents an experimental method to investigate the fracture behavior of ATJ graphite at elevated temperatures. In particular, the effects of major parameters such as temperature, loading, and oxidation conditions on strength and fracture characteristics were investigated. Uniaxial compression and tension tests were conducted in accordance with the ASTM standard at room temperature, $500^{\circ}C$, and $1,000^{\circ}C$. Fractography analysis of the fractured specimens was carried out using an SEM.