• Title/Summary/Keyword: Fe-Ni alloy

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Determination of Material Parameters for Microstructure Prediction Model Based on Recystallization and Grain Growth Behaviors (재결정 및 결정립 성장거동을 기초한 조직예측 모델에 대한 변수 결정방법)

  • Yeom, J.T.;Kim, J.H.;Hong, J.K.;Park, N.K.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.05a
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    • pp.270-273
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    • 2009
  • This work describes a method of determining material parameters included in recrystallization and grain growth models. Focus is on the recrystallization and grain growth models of Ni-Fe base superalloy, Alloy 718. High temperature compression tests at different strain, strain rate and temperature conditions were chosen to determine the material parameters of dynamic recrystallization model. The critical strain and dynamically recrystallized grain size and fraction at various process variables were quantitated with the microstructual analysis and strain-stress relationships of the compression tests. Besides, isothermal heat treatments were utilized to fit the material constants included in the grain growth model. Verification of the determined material parameters is carried out by comparing the measured data obtained from other compression tests.

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The Study of Effect of EDTA(Ethylenediaminetetraacetic acid) to the defected Ni-Cr-Fe Alloy in the Steam Generator Chemical Cleaning of the Nuclear Power Plant (원전 SG 화학세정 환경에서 EDTA가 결함 Ni-Cr-Fe 합금에 미치는 영향 연구)

  • Gwon, Hyeok-Cheol;Lee, Han-Cheol;Seong, Gi-Bang
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2013.05a
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    • pp.117-118
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    • 2013
  • 증기발생기 화학세정 모사 장치를 이용하여 고농도 화학세정(EPRI/SGOG) 용액인 EDTA(20%)가 인위적으로 제작한 결합 시편에 미치는 영향 평가를 수행하였다. 평가 방법은 세정 전 후 표면 산화막 성분, ECT 분석값 비교, 증기발생기 구성 재료 부식률를 이용하였다. 화학세정 전후 부식률은 A508은 $8.023{\mu}m$, Alloy 600(HTMA)은 $0.007{\mu}m$이며 갈바닉 시편의 경우 $63.193{\mu}m$로 모두 부식 허용치 이내이다. 표면 산화막 성분 및 ECT 분석값 역시 변함이 없었다. 이와 같은 결과로 화학세정 용액인 EDTA는 결함 튜브에 미치는 영향이 없는 것으로 판단된다.

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Austenite Stability of Nanocrystalline FeMnNiC Alloy (나노결정 FeMnNiC합금의 오스테나이트 안정성)

  • Oh, Seung-Jin;Jeon, Junhyub;Shon, In-Jin;Lee, Seok-Jae
    • Journal of Powder Materials
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    • v.26 no.5
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    • pp.389-394
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    • 2019
  • In the present study, we have investigated the effect of sintering process conditions on the stability of the austenite phase in the nanocrystalline Fe-5wt.%Mn-0.2wt.%C alloy. The stability and volume fraction of the austenite phase are the key factors that determine the mechanical properties of FeMnC alloys, because strain-induced austenite-martensite transformation occurs under the application of an external stress at room temperature. Nanocrystalline Fe-5wt.%Mn-0.2wt.%C samples are fabricated using the spark plasma sintering method. The stability of the austenite phase in the sintered samples is evaluated by X-ray diffraction analysis and hardness test. The volume fraction of austenite at room temperature increases as the sample is held for 10 min at the sintering temperature, because of carbon diffusion in austenite. Moreover, water quenching effectively prevents the formation of cementite during cooling, resulting in a higher volume fraction of austenite. Furthermore, it is found that the hardness is influenced by both the austenite carbon content and volume fraction.

Effect of Cu Dopping in Fe-35%Ni Sheet on Electromagnetic Properties (구리농도에 따른 Fe-Ni박막의 전자기적 특성에 대한 효과)

  • Han, S.S.;Koo, DY;Choi, Y.
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2015.11a
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    • pp.344-345
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    • 2015
  • Various concentration of copper was dopped in Fe-35%Ni thin sheet by electroforming and their electromagnetic, surface properties were determined. Microstructure observation by scanning electron microscopy revealed that the thin sheet had columnar grains with about 150 nm long. Phase analysis by X-ray diffractometry revealed that the alloy thin sheets were fine crystalline. The average surface roughnesses measured by atomic force microscopy (AFM) were about 14.38 nm. Nano hardnesses determined by tribo-nano indenter were 4.13 GPa. The surface resistances were 2.28 ohm/sq. The maximum magnetization, residual magnetization and coercive force depended on the copper concentration.

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Electrochemical Behavior and Biocompatibility of Co-Cr Dental Alloys

  • Kang, Jung-In;Yoon, Jun-Bin;Choe, Han-Cheol
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2015.05a
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    • pp.107-107
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    • 2015
  • In order to investigate electrochemical behavior and biocompatibility of Co-Cr dental alloy by electrochemical corrosion test and MTT assay, the xCo-25Cr-yW-zNi alloys were used in this study. Samples of Co-Cr-W-Ni alloys were manufactured using arc melting furnace. The microstructure of the alloys was examined by optical microscopy (OM), Field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), MTT assay, and corrosion test. Corrosion resistance increased slightly as cobalt (Co) content increased. And bioactivity was concerned with nickel (Ni) and tungsten (W). Biocompatibility of Co-Cr alloy depended on Ni and W contents.

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