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Causes of the formation of longitudinal surface cracks on the DC-cast 7039 aluminium alloy

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Abstract

The longitudinal surface cracks occurring on the DC-cast 7039 aluminium alloy were investigated. The cracks were characterized by a grooved appearance on the exterior surface and a branching and porous morphology in the interior area. Microscopic analysis showed that the crack opening was of an abnormal chilled structure, while the interior region was of slowly solidified structures. EPMA and DTA indicated that Mg-Zn intermetallic compounds were formed in the crack interior boundaries. The results suggested that the cracks originated from the uneven chill conditions of the mould. The liquid melt in front of the hot spot was enclosed by the rapidly growing solidified shell and the bridged liquid melt then suffered from a slow cooling rate, forming shrinkage cracks and pores. Formation of Mg-Zn intermetallic compound arising from the slow solidification may enhance the crack occurrence. The cracks were completely eliminated by the improvement in the mould cooling efficiency.

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References

  1. R. Grimes,Metal Sci. 8 (1974) 176.

    Google Scholar 

  2. C. M. Jackson andE. H. Welch,Sheet Metal Ind. 52 (1975) 34.

    Google Scholar 

  3. E. Baschmann,Z. Metallkde 59 (1968) 372.

    Google Scholar 

  4. R. S. Clegg andC. M. Jackson,Metals Technol. 2 (1975) 120.

    Google Scholar 

  5. A. Sendorek andR. W. Thomas, in International Symposium on Anodising, Birmingham, 1967, p. 97.

  6. E. F. fnEmley,Int. Met. Rev. June (1976) 75.

  7. R. Bachowski andR. E. Spear, in “Light Metals 1975”, Vol. 2 (AIME, 1975) p. I 11.

  8. A. T. Taylor, D. H. Thompson andJ. J. Wegner,Metal Prog. Nov. (1975) p. 70.

  9. J. Moriceau, in “Light Metals 1975”, Vol. 2 (AIME, 1975) p. 119.

  10. K. Buxmann,ibid, p. 135.

  11. D. L. W. Collins,Metallurgia 76 (1967) 137.

    Google Scholar 

  12. D. J. Strawbridge, W. Hume-Rothery andA. T. Little,J. Inst. Metals. 74 (1974) 191.

    Google Scholar 

  13. M. C. Flemings, in “Solidification Processing”, (McGraw-Hill, New York, 1974) p. 58.

    Google Scholar 

  14. L. F. Mondolfo, in “Aluminium Alloys, Structure and Properties” (Butterworths, London-Boston, 1976) p. 578.

    Google Scholar 

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Authors and Affiliations

  1. China Steel Corporation, Kaohsiung, Taiwan

    C. S. Wu

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  1. C. S. Wu
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Wu, C.S. Causes of the formation of longitudinal surface cracks on the DC-cast 7039 aluminium alloy. J Mater Sci 23, 606–610 (1988). https://doi.org/10.1007/BF01174693

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  • DOI: https://doi.org/10.1007/BF01174693

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