DOI QR코드

DOI QR Code

DCPD법을 이용한 분말야금 니켈기 초내열합금의 고온 피로균열진전거동

Fatigue Crack Growth Behavior of Powder Metallurgical Nickel-based Superalloy using DCPD Method at Elevated Temperature

  • Na, Seonghyeon (School of Mechanical Engineering, Chungnam National University) ;
  • Oh, Kwangkeun (School of Mechanical Engineering, Chungnam National University) ;
  • Kim, Hongkyu (The 4th R&D Institute - 4th Directorate, Agency for Defense Development) ;
  • Kim, Donghoon (The 4th R&D Institute - 4th Directorate, Agency for Defense Development) ;
  • Kim, Jaehoon (School of Mechanical Engineering, Chungnam National University)
  • 투고 : 2015.12.01
  • 심사 : 2016.03.14
  • 발행 : 2016.04.01

초록

분말야금 니켈기 초내열합금은 항공기 터빈 엔진의 고온용 부품으로 사용되고 있다. 본 연구에서는 상온, $600^{\circ}C$$700^{\circ}C$에서 CT시편을 이용하여 피로균열진전거동이 평가되었다. ASTM E647에서 제시한 직류전위차법이 피로균열진전 동안에 균열 길이를 측정하기 위하여 사용되었다. 응력비 0.5에서 피로균열진전속도는 응력비 0.1에서와 비교하여 더 빠르게 나타났다. 피로균열진전속도는 응력비와 온도의 증가와 함께 증가하였다. 파단면 관찰은 파괴메커니즘 분석을 위해 수행하였다.

Powder metallurgy nickel based superalloy has been used in a high temperature part of turbine engine for airplane. The fatigue crack growth behavior was investigated using CT specimens for the materials at room temperature(R.T.), $600^{\circ}C$ and $700^{\circ}C$. The direct current potential drop(DCPD) method suggested by ASTM E647 was used to measure the crack length during fatigue crack growth at various stress ratios. The fatigue crack growth rate at R=0.5 was faster than that at R=0.1 for all temperature conditions and increased with the increase of stress ratio and temperature. Fractography was conducted for analysis of fracture mechanism.

키워드

참고문헌

  1. Oh, Y.J., Kim, J.H. and Hwang, I.S., "Dynamic Loading Fracture Tests of Ferritic Steel Using Direct Current Potential Drop Method," Journal of Testing and Evaluation, Vol. 30, No. 3, pp. 221-227, 2002. https://doi.org/10.1520/JTE12309J
  2. Zhang, L.N., Wang, P., Dong, J.X. and Zhang, M. C., "Microstructures' Effects on High Temperature Fatigue Failure Behavior of Typical Superalloys," Materials Science and Engineering A, Vol. 587, pp. 168-178, 2013. https://doi.org/10.1016/j.msea.2013.08.065
  3. Luo, J. and Bowen, P., "Small and Long Fatigue Crack Growth Behaviour of a PM Ni-Based," International Journal of Fatigue, Vol. 26, Issue 2, pp. 113-124, 2004. https://doi.org/10.1016/S0142-1123(03)00139-7
  4. Yang, H., Bao, R., Zhang, J., Peng, L. and Fei, B., "Crack Growth Behaviour of a Nickel-Based Powder Metallurgy Superalloy Under Elevated Temperature," International Journal of Fatigue, Vol. 33, Issue 4, pp. 632-641, 2011. https://doi.org/10.1016/j.ijfatigue.2010.11.003
  5. ASTM E647-15, "Standard Test Method for Measurement of Fatigue Crack Growth Rates," ASTM International, West Conshohocken, PA, 2015.
  6. Gustafsson, D., Moverare, J., Johansson, S, Hörnqvistd, M., Simonssona, K., Sjöströma, C. S. and Sharifimajdaa, B., "Fatigue Crack Growth Behaviour of Inconel 718 with High Temperature Hold Times," Procedia Engineering, Vol. 2, Issue 1, pp. 1095-1104, 2010. https://doi.org/10.1016/j.proeng.2010.03.118
  7. Kang, C.Y., "Fracture Mechanism and Micro Practography - Intergranular Fracture and Fracture at High Temperature," Journal of KWS, Vol. 22, No. 3, pp. 6-8, 2004.