Al 첨가 TWIP강에서의 지연파괴에 대한 변형유기 마르텐사이트 변태의 영향

Effects of the Strain Induced Martensite Transformation on the Delayed Fracture for Al-added TWIP Steel

  • Kim, Youngwoo (Depart. of Mater. Sci. & Eng., Pusan National University) ;
  • Kang, Namhyun (Depart. of Mater. Sci. & Eng., Pusan National University) ;
  • Park, Youngdo (Depart. of Adv. Mater. Eng., Dongeui University) ;
  • Choi, Ildong (Div. of Mech. & Mater. Eng., Korea Maritime University) ;
  • Kim, Gyosung (POSCO Technical Research Laboratory) ;
  • Kim, Sungkyu (POSCO Technical Research Laboratory) ;
  • Cho, Kyungmox (Depart. of Mater. Sci. & Eng., Pusan National University)
  • 투고 : 2008.09.13
  • 발행 : 2008.12.25

초록

For the advanced high strength steels (AHSS), high-manganese TWIP (twinning induced plasticity) steels exhibit high tensile strength (800-1000 MPa) and high elongation (50-60%). However, the TWIP steels need to be understood of delayed fracture following the cup drawing test. Among the factors to cause delayed fracture, i.e, martensite transformation, hydrogen embrittlement and residual stress, the effects of martensite transformation (${\gamma}{\rightarrow}{\varepsilon}$ or ${\gamma}{\rightarrow}{\alpha}^{\prime}$) were investigated on the delayed fracture phenomenon. Microstructural phase analysis was conducted for cold rolled (20, 60, 80% reduction ratio) steels and tensile deformed (20, 40, 60% strain) steels. For the Al-added TWIP steels, no martensite phase was found in the cold rolled and tensile deformed specimen. But, the TWIP steels with no Al addition indicated the martensite transformation. The cup drawing specimens showed the martensite transformation irrespective of the Al-addition to the TWIP steel. However, the TWIP steel with no Al exhibited the larger amount of martensite than the case of the TWIP steel with Al addition. For the reason, it was possible to conclude that the Al addition suppressed the martensite transformation in TWIP steels, therefore preventing the delayed fracture effectively. However, it was interesting to note that the mechanism of delayed fracture should be incorporated with hydrogen embrittlement and/or residual stress as well as the martensite transformation.

키워드

과제정보

연구 과제 주관 기관 : POSCO

참고문헌

  1. G.G. Chin, S.G. Kim, S.K. Kim and I.R. Sohn, Tre. Met. Mater. Eng. 19, 12 (2006)
  2. G. Frommeyer, U. Brux, P. Neumann, ISIJ Int. 43, 438 (2003) https://doi.org/10.2355/isijinternational.43.438
  3. M.R. Berrahmoune, S. Berveiller, K. Inal and E. Patoor, Mater. Sci. Eng. A 438-440, 262 (2006)
  4. M. Nagumo, S. Sekiguchi, H. Hayashi and K. Takai, Mater. Sci. Eng. A 344, 86 (2003) https://doi.org/10.1016/S0921-5093(02)00403-3
  5. N.R. Moody, TMS-AIME, p.537, Warrendale, PA (2003)
  6. A.S. Hamada, L.P. Karjalainen and M.C. Somani, Mater. Sci. Eng. A 467, 114 (2007) https://doi.org/10.1016/j.msea.2007.02.074
  7. S. Allain, J.P. Chateau, O. Bouaziz, S. Migot and N. Guelton, Mater. Sci. Eng. A 387-389, 158 (2004).
  8. B.X. Huang, X.D. Wang, Y.H. Rong, L. Wang and L. Jin, Mater. Sci. Eng. A 438-440, 306 (2006)
  9. M. Koyama, T. Sawaguchi, K. Ogawa, T. Kikuchi and M. Murakami, Mater. Sci. Eng. A 497, 353 (2008) https://doi.org/10.1016/j.msea.2008.07.026
  10. B.D Cullity, Elements of X-ray Diffraction, 2nd ed., Addison Wesley (1978)
  11. C.M Kim, J. Heat Treat. 1, 43 (1979) https://doi.org/10.1007/BF02833237
  12. S.K. Kim, G.S. Kim and K.G. Chin, Int. Conf. p.249-256, Dev. AHSS, June (2008)
  13. L.Remy and A.Pineau, Mater. Sci. Eng. 28, 99 (1977) https://doi.org/10.1016/0025-5416(77)90093-3
  14. Hirth JP, Metall. Trans. 1, 2367 (1970)
  15. Miodowink AP, Calphad 2, 207 (1998) https://doi.org/10.1016/0364-5916(78)90010-X
  16. Ferreira PJ and Mullner P, Acta Mater. 46, 4479 (1998) https://doi.org/10.1016/S1359-6454(98)00155-4
  17. Lee YK and Choi CS, Metall Mater. Trans. 31 A, 355 (2000)
  18. Xing Tian, Hong Li and Yansheng Zhang, J. Mater. Sci. 43, 6214 (2008) https://doi.org/10.1007/s10853-008-2919-0
  19. Ishida K, Phys. Stat. Solids 36, 717 (1976) https://doi.org/10.1002/pssa.2210360233
  20. C. Pan, W.Y. Chu, Z.B. Li, D.T. Liang, Y.J. Su, K.W. Gao and L.J. Qiao, Mater. Sci. Eng. A 351, 293(2003) https://doi.org/10.1016/S0921-5093(02)00856-0
  21. V.N. Shivanyuk, J. Foct and V.G. Gavriljuk, Scrip. Mater. 49, 601 (2003) https://doi.org/10.1016/S1359-6462(03)00338-5
  22. M. Nagumo, M. Nakamura and K. Takai, Metal. Mater. Trans. 32A, 335 (2001)
  23. H.G. Chun and S.W. Nam, UIT Report 13, 383 (1982)
  24. S.P. Lynch, Metals Forum 2, 189 (1979)