Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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The Effect of Post-Bond Heat Treatment on Tensile Property of Diffusion Bonded Austenitic Alloys

확산 접합된 오스테나이트계 재료의 인장특성에 미치는 후열처리의 영향

  • Hong, Sunghoon (Dept. of Nuclear and Quantum Engineering, KAIST) ;
  • Kim, Sung Hwan (Dept. of Nuclear and Quantum Engineering, KAIST) ;
  • Jang, Changheui (Dept. of Nuclear and Quantum Engineering, KAIST) ;
  • Sah, Injin (Nuclear Hydrogen Reactor Technology Development Division, KAERI)
  • 홍성훈 (한국과학기술원 원자력 및 양자공학과) ;
  • 김성환 (한국과학기술원 원자력 및 양자공학과) ;
  • 장창희 (한국과학기술원 원자력 및 양자공학과) ;
  • 사인진 (한국원자력연구원 수소생산원자로기술개발부)
  • Received : 2015.06.13
  • Accepted : 2015.10.14
  • Published : 2015.12.01
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Abstract

Diffusion bonding is the key manufacturing process for the micro-channel type heat exchangers. In this study, austenitic alloys such as Alloy 800HT, Alloy 690, and Alloy 600, were diffusion bonded at various temperatures and the tensile properties were measured up to $650^{\circ}C$. Tensile ductility of diffusion bonded Alloy 800HT was significantly lower than that of base metal at all test temperatures. While, for Alloy 690 and Alloy 600, tensile ductility of diffusion bonded specimens was comparable to that of base metals up to $500^{\circ}C$, above which the ductility became lower. The poor ductility of diffusion bonded specimen could have caused by the incomplete grain boundary migration and precipitates along the bond-line. Application of post-bond heat treatment (PBHT) improved the ductility close to that of base metals up to $550^{\circ}C$. Changes in tensile properties were discussed in view of the microstructure in the diffusion-bonded area.

미세유로채널 타입의 열교환기 제작에 필요한 과정 중 하나인 확산접합(Diffusion Bonding)에 대하여 연구를 수행하였다. 시험에 사된 재료는 Alloy 800HT, Alloy 690, 그리고 Alloy 600 으로 다양한 온도에서 확산접합을 수행하고 상온에서 $650^{\circ}C$ 까지 인장특성을 평가하였다. Alloy 800H 의 경우 든 온도에서 확산접합부의 연신율이 크게 저하되었다. Alloy 690 과 Alloy 600 의 경우 $500^{\circ}C$ 까지는 확산접합부도 높은 연신율을 보이나 $550^{\circ}C$ 이상에서는 연신율이 재에 비해 감소하였다. 이는 확산접합부에서의 불분한 결정립계 이동과 석출상에 의한 것으로 판단된다. 확산접합부의 인장 특성을 향상시키기 위해 후열처리를 수행한 경우 든 재료에 대해 $550^{\circ}C$ 까지 재 수준으로 연신율이 회복되었다. 이러한 확산접합부의 인장특성의 변화와 미세조직간의 연관성에 대해 토의하였다.

Keywords

References

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