Journal of the Korean Society for Heat Treatment (열처리공학회지)

The Korean Society for Heat Treatment (한국열처리공학회)
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Effects of Ti Addition on Microstructure and Mechanical Properties of Mg-xAl-yZn Magnesium Alloys by Thixomolding Process

Thixomolding 공정으로 제조된 Mg-xAl-yZn계 마그네슘 합금의 미세조직과 기계적 물성에 미치는 Ti 첨가 영향

  • Park, Sung-Hyun (School of Materials Science and Engineering, Kumoh National Institute of Technology (KIT)) ;
  • Jang, Ho-Seung (School of Materials Science and Engineering, Kumoh National Institute of Technology (KIT)) ;
  • Lee, Ji-Ho (School of Materials Science and Engineering, Kumoh National Institute of Technology (KIT)) ;
  • Park, No-Jin (School of Materials Science and Engineering, Kumoh National Institute of Technology (KIT)) ;
  • Oh, Myung-Hoon (School of Materials Science and Engineering, Kumoh National Institute of Technology (KIT))
  • 박성현 (금오공과대학교 신소재공학부) ;
  • 장호승 (금오공과대학교 신소재공학부) ;
  • 이지호 (금오공과대학교 신소재공학부) ;
  • 박노진 (금오공과대학교 신소재공학부) ;
  • 오명훈 (금오공과대학교 신소재공학부)
  • Received : 2019.07.05
  • Accepted : 2019.07.25
  • Published : 2019.07.30
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Abstract

The microstructural features and relative room temperature mechanical properties were investigated in various compositions of Mg-xAl-yZn alloys by thxiomolding process. The microstructure was composed of ${\alpha}$-Mg particles and mixture of ${\alpha}$-Mg and ${\beta}-Mg_{17}Al_{12}$ eutectic phase. The amount of ${\beta}-Mg_{17}Al_{12}$ eutectic phase in mixture was increased with increasing Al and Zn contents without grain refinement. After adding Ti content, however, the morphology of ${\beta}-Mg_{17}Al_{12}$ eutectic phase transformed from net-like to discontinuous shape and the average grain size reduced. To determine the relationship between microstructural features and their mechanical properties, a tensile test was performed at room temperature. As a result, it was found that the mechanical properties were improved in all of Ti contained alloys due to increased elongation and the mechanisms are discussed in terms of microstructural evolution.

Keywords

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Fig. 1. Binary equilibrium phase diagram of Al-Mg system [4].

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Fig. 2. XRD patterns of AZ72, AZ81 and AZ82 alloys in as-cast state, respectively.

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Fig. 3. Optical micrographs of (a) AZ72, (b) AZ81 and (c) AZ82 alloys in as-cast state.

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Fig. 4. Results of higher magnification optical microscopy observation obtained from (a) AZ72, (b) AZ81 and (c) AZ82,respectively.

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Fig. 5. Average grain size of (a)AZ72 and (b)AZ72+Ti alloys measured from higher magnification.

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Fig. 6. SEM observations of β-Mg17Al12 morphology obtained from (a) AZ72, (b) AZ72+Ti, (c) AZ81 and (d) AZ82, respectively

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Fig. 7. Variation in tensile properties of Mg-xAl-yZn alloys according to change of Al and Zn amount in ascast state.

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Fig. 8. Effect of Ti addition on tensile properties of Mg-xAl-yZn alloys in as-cast state.

Table 1. Chemical compositions of magnesium alloys used in this study

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Table 2. Summary of room temperature tensile properties obtained from Mg-xAl-yZn and Mg-xAl-yZn+0.4Ti (wt.%) alloys in as-cast state

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References

  1. K. U. Kainer : International Conference on Magnesium Alloys and Their Application, 7th, WILEY-VCH, Weinheim, Germany (2006) 985.
  2. F. Czerwinski, A. Zielinska-lipiec, P. J. Pinet, and Overbeeke, J. : Acta mater., 49 (2001) 1225-1235. https://doi.org/10.1016/S1359-6454(01)00015-5
  3. G. Petterson, H. Westengen, R. Hoier and O. Lohne : Mater. Sci. Eng. A, 207 (1996) 115-120. https://doi.org/10.1016/0921-5093(95)10035-0
  4. Thaddeus B. Massalski : Binary Alloy Phase Diagrams, 2nd, ASM, OH, USA (1986) 170.
  5. Y. C. Lee, A. K. Dahle, and D. h. StJohn : Metall. Mater. Trans. A, 31 (2000) 2895-2906. https://doi.org/10.1007/BF02830349
  6. Z. Yu, A. Tang, L. Zhang and F. Pan : Mater. Sci., 30 (2014) 1441-1446.
  7. Arne K. Dahle, Young C. Lee, Mark D. Nave, Paul L. Schaffer and David H. StJohn : JLM., 1 (2001) 61-72.
  8. Y. Turen : Mater. Des., 49 (2013) 1009-1015.
  9. S. Candan, M. Unal, E. Koc, Y. Turen and E. Candan : J Alloys Compd., 509 (2011) 1958-1963. https://doi.org/10.1016/j.jallcom.2010.10.100
  10. D. Ghosh, K. Kang, C. Bach, J. G. Romer and C. van Schilt : In Proceedings of the 34 Annual Conference of Metallurgists of CIM., Vancouver (1995) 481.
  11. R. Carnahan, R. Hathaway, R. Kilbert, L. Pasternak and P. Rohatgi : Proc. of the International Symposium on Light Metals Processing and Applications, CIM, Quebec (1993) 325.
  12. William D. Callister, JR., David G. Rethwisch : Materials Science and Engineering, 9th, John Wiley&Sons, Inc., Singapore, (2015) 280, 422, 432.
  13. Alireza Ghaderi and Matthew R. Barnett : Acta mater., 59 (2011) 7824-7839. https://doi.org/10.1016/j.actamat.2011.09.018