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Microstructures and Mechanical Properties of Age Hardenable Cu-2.0wt%Be Alloy for Projection Welding Electrode

프로젝션 용접 전극을 위한 시효경화성 Cu-2.0wt%Be 합금의 미세조직과 기계적성질

  • 김광수 (순천향대학교 디스플레이.신소재공학과) ;
  • 김진용 (코리아세미텍(주))
  • Received : 2015.07.24
  • Accepted : 2015.08.18
  • Published : 2015.09.27

Abstract

Evaluations of the microstructure and mechanical properties of age hardenable Cu-2.0wt%Be alloy are performed in order to determine whether it can be used as a welding electrode for projection welding. The microstructure examinations, hardness measurements, and tensile tests of selective aging conditions are conducted. The results indicate that the aging treatment with the fine-grained microstructure exhibits better hardness and high tensile properties than those of the coarse-grained microstructure. The highest hardness value and high tensile strength are obtained from the aged condition of $300^{\circ}C$ for 360 min due to the presence of the metastable ${\dot{\gamma}}$ precipitates on the grain boundaries. The values of the highest hardness and tensile strength are measured as 374 Hv and 1236.2 MPa, respectively. The metastable ${\dot{\gamma}}$ precipitates are transferred to the equilibrium ${\gamma}$ precipitates due to the over-aged treatment. The presence of the ${\gamma}$ precipitates appears as nodule-like precipitates decorated around the grain boundaries. The welding electrode with the best aging treated condition exhibits better welding performance for electrodes than those of electrodes used previously.

References

  1. W. F. Smith, Structure and properties of engineering alloys, McGraw-Hill, 2nd ed., p.256, (1993).
  2. R. J. Rioja and D. E. Laughlin, Acta Metall. Mater., 28, 1301 (1980). https://doi.org/10.1016/0001-6160(80)90086-3
  3. B. Cheong, K. Hono and D. E. Laughlin, Acta Metall Mater., 42, 2387 (1994). https://doi.org/10.1016/0956-7151(94)90317-4
  4. M. Ryou, B. S. Lee and M. H. Kim, J. Mater. Sci. Technol., 24, 120 (2008).
  5. Copper Development Association Inc, www.copper.org, Copper and Copper-Beryllium Alloy.
  6. P. Wilkes, Acta Metall. Mater., 16, 153 (1968). https://doi.org/10.1016/0001-6160(68)90110-7
  7. F. Lu and P. Dong, Sci. Technol. Weld. Joining, 4, 285 (1999). https://doi.org/10.1179/136217199101537888
  8. K. L. Chatterjee and W. Waddell, Weld. Met. Fab. 64, 110 (1996).
  9. S. Fukumoto, I. Lum, E. Biro, D. R. Boomer and Y. Zhou, Weld. J. 82, 307-312s. (2003).
  10. K. R. Chan, Ph. D. Thesis (in English), p.14-20, University of Waterloo, Waterloo (2005).
  11. T. V. Nordstrom, R. W. Rohde and D. J. Mottern, Metall. Trans A. 6A, 1561 (1975).
  12. A A. Ezra : Garden City Press, Ltd., Letchworth, Hertfordshire, Great Britain, "Principles and Pracice of Explosive Metal Working", 234 (1973).
  13. Keith G. Wikle : "Beryllium copper an overview of heat techniques, Heat treating", ASM, July, 30 (1983).
  14. J. Zhang, R. J. Perez, C. R Wong and E. J. Lavernia, Mater. Sci. Eng., 13, 325 (1994). https://doi.org/10.1016/0927-796X(94)90010-8
  15. R. Monzen, T. Hasegawa and C. Watanabe, Philos. Mag. Lett., 89, 75 (2009). https://doi.org/10.1080/09500830802537700
  16. LECO corp. Metallography Principles and Procedure, 42 (1996).
  17. A. Mance and A Mihajloviv, J. Appl. Electrochem., 11, 205 (1981). https://doi.org/10.1007/BF00610982
  18. A. G. Khachaturyan, D. E. Laughlin, Acta Metall. Mater., 38, 1823 (1990). https://doi.org/10.1016/0956-7151(90)90294-Q