• Title/Summary/Keyword: 니켈기 초합금

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Rejuvenation Technologies for Hot Gas Path Components made of Nickel Based Superalloys (니켈기 초합금 소재 고온부 부품의 재생정비기술)

  • Kang, Sin-Ho;Choi, Heui-Sook;Kim, Dae-Eun
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.424-429
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    • 2003

  • Hot gas path components, which are made of nickel based superalloys, are subject to periodic replacement due to degradation of thermomechanical properties that might bring catastrophic failure during normal operation of gas turbine units. In order to rejuvenate the metallurgical condition of the serviced components, heat treating techniques such as solution annealing and aging heat treatments have widely been employed. However, the effectiveness of those typical heat treatments is not apparent enough in terms of quantitative grounds. On the other hand the demand of the rejuvenation heat treatment and hot isostatic pressing (HIP) have constantly been raised by the end users. Therefore it is necessary to verify how the typical heat treating techniques affect to the aged and degraded material. As the result of experimental work in this study, GTD-111 and GTD-222 Ni-based superalloys were collected and analyzed quantitatively through microscopic observation, microhardness evaluation and creep test.

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Evaluation of Fatigue Crack Propagation Behavior of Nickel-based Powder Metallurgy Superalloy for Aircraft at Elevated Temperature (항공기 터빈 디스크용 니켈기 초내열 분말야금 합금의 고온 피로균열진전 거동 비교 평가)

  • Yoon, Dong Hyun;Na, Seong Hyeon;Kim, Jae Hoon;Kim, Hongkyu;Kim, Donghoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.8
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    • pp.751-758
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    • 2017

  • The behavior of fatigue crack growth of nickel-based powder metallurgy superalloy that could be used in aircraft turbine disc is investigated at room temperature, and $650^{\circ}C$ considering real operating conditions. The direct current potential drop(DCPD) method was used to measure the crack length of material in real time according to ASTM E647. Tests were performed with various stress ratios (0.1 and 0.5). Experimental results show that stress ratio, and temperature all affect the behavior of fatigue crack growth. As the stress ratio and temperature increase, the fatigue crack growth rate of nickel-based powder metallurgy superalloy also increases. Results were compared and reviewed with fatigue crack growth rates of other nickel-based superalloy materials (Inconel-100) that were studied in previous papers. Fractography analysis of the fractured specimens was performed using as SEM.

  • https://doi.org/10.3795/KSME-A.2017.41.8.751 인용 PDF KSCI

형상기억합금의 특성 및 응용

  • Lee, In;Yang, Seung-Man
    • Journal of the KSME
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    • v.44 no.6
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    • pp.34-39
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    • 2004

  • 형상기억합금(SMA : Shape Memory Alloy)은 일반적인 금속이나 합금에서는 찾아볼 수 없는 형상기억효과(shape memory effect)와 초탄성 (superelasticity) 거동을 보이고 있다. 이러한 특성은 1951년에 금-카드뮴(Au-Cd) 합금에서 처음으로 발견되었으며, 1963년에 미국 해군병기연구소(Naval Ordnance Laboratory)에서 니켈-티타늄 (Ni-Ti) 합금에서 형상기억효과를 발견한 후로 널리 상용화되었다. 니티놀(nitinol)이라고 불려지는 니켈-티타늄 계열의 형상기억합금은 단위 부피당 많은 에너지를 낼 수 있고, 내 부식성(corrosion resistance)과 생화학적 적합성(bio-compatibility)이 뛰어나다. 또한 100,000사이클 이상의 긴 사용수명을 갖기 때문에 작동기(actuator)로서 우수한 특징을 갖는다. (중략)

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Degradation Quantification Method and Degradation and Creep Life Prediction Method for Nickel-Based Superalloys Based on Bayesian Inference (베이지안 추론 기반 니켈기 초합금의 열화도 정량화 방법과 열화도 및 크리프 수명 예측의 방법)

  • Junsang, Yu;Hayoung, Oh
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.27 no.1
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    • pp.15-26
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    • 2023

  • The purpose of this study is to determine the artificial intelligence-based degradation index from the image of the cross-section of the microstructure taken with a scanning electron microscope of the specimen obtained by the creep test of DA-5161 SX, a nickel-based superalloy used as a material for high-temperature parts. It proposes a new method of quantification and proposes a model that predicts degradation based on Bayesian inference without destroying components of high-temperature parts of operating equipment and a creep life prediction model that predicts Larson-Miller Parameter (LMP). It is proposed that the new degradation indexing method that infers a consistent representative value from a small amount of images based on the geometrical characteristics of the gamma prime phase, a nickel-base superalloy microstructure, and the prediction method of degradation index and LMP with information on the environmental conditions of the material without destroying high-temperature parts.

  • https://doi.org/10.6109/jkiice.2023.27.1.15 인용 PDF