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Microstructural Changes and Mechanical Properties of 7175 Aluminum Alloy Die Forgings

7175 알루미늄합금 형단조재의 미세조직 변화와 기계적 성질

  • 이인기 (전북대학교 신소재공학부, 자동차신기술연구센터) ;
  • 유재선 (전북대학교 신소재공학부, 자동차신기술연구센터) ;
  • 강성수 (전북대학교 신소재공학부, 자동차신기술연구센터) ;
  • 이오연 (전북대학교 신소재공학부, 자동차신기술연구센터)
  • Published : 2004.03.01

Abstract

The aim of this study is to investigate the effect of process conditions on the microstructual changes and mechanical properties of large 7175 aluminum die forgings. The cast billets of 370 and 720 mm in diameter were homogenized and die forged after direct chill casting. The size and volume fraction of second phase particles in 720 mm billet were larger than those of 370 mm billet. The interdendritic sites containing the second phase particles was considered to be a crack initiation region in the process of cold upsetting. The tensile and yield strength of die forged specimens of 720 mm billet in the direction of Land L T were higher than those of 370 mm billet. However, the tensile strength of these specimens were 5 to 10% lower than that of American military specification. The plane strain fracture toughness of die forged specimens of 370 mm cast billet showed almost the same level of 720 mm billet, which was die forged after free forging.

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References

  1. A. J. Sedrikes, P. W. Slatteuy and E. N. Pugh, Trans, ASM, 62, 238 (1969)
  2. A. J. DeArdo and R. W. Townsend, Metall. Trans., 1, 2573 (1979)
  3. H. A. Hall, J. Inst. Met. 6, 631 (1975)
  4. U. S. Patent 3198676 (1965)
  5. M. V. Hyatt, Metal Progress, 9, 56 (1977)
  6. K. Higashi, Y. Hirai and T. Ohnishi, Light Metals, 35, 520 (1985) https://doi.org/10.2464/jilm.35.520
  7. Y. Baba, Light Metals, 39, 378 (1989) https://doi.org/10.2464/jilm.39.378
  8. G. G. Garrett and J. F. Kontt, Metall. Trans., 9, 1187 (1978) https://doi.org/10.1007/BF02652242
  9. M. Gao, P. S. Pao and R. P. Wei, Metall. Trans., 19, 1739 (1988) https://doi.org/10.1007/BF02645142
  10. J. S. Santner, Metall. Trans, 9, 769 (1978) https://doi.org/10.1007/BF02649786
  11. G. T. Hahn and A. R. Rosenfield, Metall. Trans., 3, 1992 (1973)