• Title/Summary/Keyword: 중성자 회절

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Measurement of Through Thickness Welding Residual Stresses based on Theory of Inherent Strain (고유변형도이론을 이용한 두께방향의 용접잔류응력의 측정)

  • Park, Jeong-Ung;Ryu, Kang-Mook;An, Gyu-Baek;Lee, Jong-Sub;Jang, Seok-In
    • Proceedings of the KWS Conference
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    • 2009.11a
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    • pp.98-98
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    • 2009

  • 용접에 의해 발생하는 용접잔류응력은 강구조물의 피로성능, 파괴양상 등에 영향을 주고 있으나 이러한 용접잔류응력을 예측하는 것은 쉽지 않다. 이러한 용접잔류응력을 예측하는 방법으로는 열탄소성해석과 같은 수치적 방법과 실험적 방법이 있다. 열탄소성해석의 경우 실제문제를 이상화하는 과정에서 매우 복잡한 모델링 기술이 필요하다. 또한, 측정방법에서는 표면의 잔류응력을 측정할 수 있는 홀드링법과 X-선법 등이 있고, 내부 잔류응력의 측정방법으로는 중성자회절법이 있다. 그러나 홀드링법의 경우, 사용범위의 한계와, 중성자회절법에서의 내부 잔류응력을 측정할 수 있는 두께의 제약이 있어 후판의 잔류응력을 측정하는 것은 한계가 있다. 따라서 본 연구에서는 용접잔류응력의 생성근원인 고유변형도를 측정하고 이것으로부터 맞대기용접에서 발생하는 두께방향의 용접잔류응력을 계측하였다.

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Study of Order-Disorder Phase Transition of $(Fe_{0.61}Ni_{0.39})_3V$V Alloy by Neutron Diffraction Method (중성자회절법을 이용한 $(Fe_{0.61}Ni_{0.39})_3V$ 합금의 규칙- 불규칙 상전이 연구)

  • 이정수;이창희
    • Korean Journal of Crystallography
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    • v.13 no.1
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    • pp.36-40
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    • 2002

  • The order-disorder phase transition of (Fe/sub 0.61/Ni/sub 0.39/)₃V alloy that is annealed at various temperatures and time conditions was sty(lied with the examination of long-range order parameter(S) by using neutron diffraction method. As a result, the structure of the sample annealed at 680℃ for 94 h was not changed; that is, it existed iii perfect disordered state and showed face-centered cubic structure. Otherwise, samples which were annealed at temperature below 640℃ showed the value of long-range order parameter with 0 < S < 1 and phase transition into simple cubic structure partly. It was found that the annealed sample at 465℃ for 144 h is the most approximated to the thermal equilibrium state from the S-T/T/sub c/ related equation of Cowley.

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Neutron Diffraction and Mössbauer Studies of Superexchange Interaction on Al Substituted Co-ferrite (Al이 치환된 Co 페라이트에 관한 뫼스바우어 분광법 및 중성자 회절 연구)

  • Kim, Sam-Jin;Myoung, Bo-Ra;Kim, Chul-Sung;Baek, Kyung-Seon
    • Journal of the Korean Magnetics Society
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    • v.16 no.6
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    • pp.287-292
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    • 2006

  • Al substituted $CoAl_{0.5}Fe_{1.5}O_{4}$ has been studied with x-ray and neutron diffraction, $M\"{o}ssbauer$ spectroscopy and magnetization measurements. $CoAl_{0.5}Fe_{1.5}O_{4}$ revealed a cubic spinel structure of ferrinmagnetic long range ordering at room temperature, with magnetic moments of $Fe^{3+}(A)(-2.29{\mu}_{B}),\;Fe^{3+}(B)(3.81\;{\mu}_{B}),\;Co^{2+}(B)(2.66{\mu}_{B})$, respectively. The temperature dependence of the magnetic hyperfine field in $^{57}Fe$ nuclei at the tetrahedral (A) and octahedral (B) sites was analyzed based on the $N\'{e}el$ theory of magnetism. In the sample of $CoAl_{0.5}Fe_{1.5}O_{4}$, the interaction A-B interaction and intrasublattice A-A superexchange interaction were antiferromagnetic with strengths of $J_{A-B}=-19.3{\pm}0.2k_{B}\;and\;J_{A-A}=-21.6{\pm}0.2k_{B}$, respectively, while the intrasublattice B-B superexchange interaction was found to be ferromagnetic with a strength of $J_{B-B}=3.8{\pm}0.2k_{B}$.

  • https://doi.org/10.4283/JKMS.2006.16.6.287 인용 PDF KSCI