Microstructural Control of AA7075 Alloy for Thixoextrusion

반용융 압출을 위한 AA7075 합금의 조직제어

  • Yoon, Young-Ok (Dept. of Adv. Mater. Eng., Sungkyunkwan Univ.) ;
  • Kim, Young-Jig (Dept. of Adv. Mater. Eng., Sungkyunkwan Univ.) ;
  • Kim, Shae-K. (Adv. Mater. Ctr., Korea Institute of Industrial Technology) ;
  • Jo, Hyung-Ho (Adv. Mater. Ctr., Korea Institute of Industrial Technology)
  • Published : 2005.12.20

Abstract

The present study focuses on 7075 aluminum wrought alloy to investigate the potential industrial applications of thixoextrusion process. The microstructural evolution of 7075 aluminum wrought alloy for thixoextrusion has been investigated as a function of isothermal holding temperature and time in the partially remelted semisolid state. The results showed that the liquid fraction increased with increasing isothermal holding temperature and time while the average grain size was inversely proportional to isothermal holding temperature and time up to 5min. However, there was no big change of liquid fraction and average grain size with respect to isothermal holding temperature and time. The important fact that the liquid fraction and average grain size were almost uniform after 5 min holding time is considered very useful for thixoextrusion in terms of process control.

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References

  1. T. Sheppard et al. : Kluwer Academic Publishers, 'Extrusion of Aluminum Alloys', (1999) 239
  2. M.C. Fleming: Metall. Trans., 'Behavior of Metal Alloys in the Semisolid State', 22A (1991) 957-981
  3. D.H. Kirkwood, Inter. Mater. Rev., 'Semisolid Metal Processing', 39 (1994) 173-189 https://doi.org/10.1179/095066094790150946
  4. K.P. Young, R. Fitze : Proc. of 3rd Int'l Conf. on Semi-Solid Processing of Alloys and Composites, 'Semi-Solid Metal Cast Aluminum Automotive Components', (1994) 155-177
  5. K. Kiuchi and S. Sugiyama: Proc. of 3rd Int'l Conf. on Semi-Solid Processing of Alloys and Composites, 'Mashy-state Extrusion, Rolling and Forging', (1994) 245-257
  6. S. Kamado and Y. Kojima: J. Jpn. Inst. Light Met., 'Semi-liquid and Semi-solid Forming Technology for Light Metals', 50 (2000) 682-688 https://doi.org/10.2464/jilm.50.682
  7. Jae-Chul Lee and Ho-In Lee: J. Kor. Inst. Met & Mater., 'Recent R&D Trend in Thixoforming Process', 10 (1997) 129-138
  8. R.M.K. Young and T. W. Clyne: Acta Metall. Mater., 'Intra-crystalline Liquation as a Result of Solute Supersaturation in Metallic Slurries', 37 (1989) 663-674 https://doi.org/10.1016/0001-6160(89)90250-2
  9. Shae Kwang Kim and Young Jig Kim: J. Kor. Inst. Met & Mater., 'Control of Liquid Fraction and Microstructure of Semisolid AZ91D Mg Alloy Slurry', 38 (2000) 1620-1625