화학공학소재연구정보센터
홈 로그인 로그아웃 연락처 사이트맵
Korean Journal of Materials Research, Vol.10, No.7, 515-521, July, 2000
Export Citation
주조용 718합금의 고온 인장 성질에 미치는 석출물의 영향
Effect of Precipitates on the High Temperature Tensile Properties of Cast Alloy 718
주동원, 조창용, 김두현, 유영수, 김인수, 조해용1, 최승주
  • 한국기계연구원 내열재료그룹
  • 1충북대학교 기계공학부
Dong-Won Joo, Chang-Yong Jo, Doo-Hyun Kim, Young-Soo Yoo, In-Soo Kim, Hae-Yong Cho1, and Seung-Joo Choe
  • Materials Processing Department, Korea Institute of Machinery and Materials, 66 Sangnam-dong, Changwon, 641-010, Korea
  • 1Depart. of Precision & Mechanical Engineering, Chungbuk National University, Cheongju, Korea
초록
주소용 718합금의 고온 인장 성질에 미치는 석축물의 영향을 상추출법과 미세조직관찰을 통해 고찰되었다. 고온 인장시험에서 760 ? C 까지는 인장강도와 연신율이 동시에 감소하였고, 그보다 높은 온도에서는 인장강도는 급격히 감소하고 연신율은 증가하였다. 고온 인장시험에의한 응력의 영향으로 인하여 γ ′ ,γ" 석출물의 양은 760 ? C 에서 최대의 값을 나타내었다. 미세한 γ ′ ,γ" 상의 석출이 최대로 일어나는 온도에서 석출물에의한 유동응력의 증가로 인해 항복강도의 저하폭이 작았으며, 연신율은 가장 낮은값을 나타내었다. 760 ? C 보다 높은 온도에서는 전체적인 석출물의 양도 감소하였고, 특히 강화석출상의 양이 적어 연화현상이 급격히 나타났다. 급격히 나타났다.
The effect of precipitates on the high temperature tensile properties of cast alloy 718 was investigated by phase extraction method and microstructural observation. The value of tensile strength and elongation gradually decreased with increasing testing temperature up to 760 ? C . Elongation of the alloy increased, while tensile strength decreased above 76 0 ? C . The amount of precipitates in the specimen that tensile tested at 760 ? C showed maximum owing to stress assisted precipitation. Therefore, the alloy exhibited the lowest value of the elongation and the degree of decrease in yield strength at this temperature due to high flow stress of precipitates. Little amount of precipitate, especially γ ' and γ ", resulted in softening of the alloy at the temperature above 760 ? C.
Keywords:Microstructure;Phase extraction method;γ ',γ "and δ precipitate;Flow stress
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