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Journal of Materials Science

, Volume 43, Issue 5, pp 1539–1545 | Cite as

Age-hardening behaviour of a spinodally decomposed low-carat gold alloy

  • Mi-Gyoung Park
  • Chin-Ho Yu
  • Hyo-Joung Seol
  • Yong Hoon Kwon
  • Hyung-Il KimEmail author
Article

Abstract

The age-hardening behaviour of a spinodally decomposed low-carat gold alloy was investigated by means of hardness test, X-ray diffraction (XRD), field emission scanning electron microscopic (FESEM) observations, and energy dispersive spectrometer (EDS). An apparent hardness increase occurred at the initial stage of the aging process without incubation periods. Then, after a plateau, the hardness increased to the maximum value, and finally, the softening by overaging occurred. The age-hardening of the specimen is characterized by the fast increasing rate in hardness and the apparent delay of softening. By aging the solution-treated specimen, the fcc α0 phase was transformed into the Ag-rich α1, Cu-rich α2, and Zn–Pd-rich β phases through the spinodal decomposition process and the metastable phase formation. The first hardening stage which occurred during the early stage of spinodal decomposition without an apparent structural change was thought to be due to the interaction of dislocation with solute-rich fluctuations. The second hardening stage after the plateau was caused by the formation of the fine block-like structure with high coherency induced by the spinodal decomposition, which corresponded to the phase transformation of the metastable Ag-rich \(\alpha '_1 \) phase into the stable Ag-rich α1 phase. The remarkably delayed softening was caused by the slow progress of coarsening and resultant chaining of the Ag-rich α1 precipitates in the Cu-rich α2 matrix due to the uniform fine scale of the structure.

Keywords

Aging Time Energy Dispersive Spectrometer Spinodal Decomposition Specimen Alloy Hardening Stage 

References

  1. 1.
    ADA (1972) Guide to dental materials and devices, 6th edn. American Dental Association, Chicago, p 183Google Scholar
  2. 2.
    Yasuda K, Ohta M (1982) J Dent Res 61:473CrossRefGoogle Scholar
  3. 3.
    Ohta M, Shiraishi T, Yamane M, Yasuda K (1983) Dent Mater J 2:10CrossRefGoogle Scholar
  4. 4.
    Nakagawa M, Yasuda K (1988) J Mater Sci 23:2975CrossRefGoogle Scholar
  5. 5.
    Udoh K, Fujiyama H, Hisatsune K, Hasaka M, Yasuda K (1992) J Mater Sci 27:504CrossRefGoogle Scholar
  6. 6.
    Kim HI, Jang MI, Jean BJ (1997) J Mater Sci Mater Med 8:333CrossRefGoogle Scholar
  7. 7.
    Hamasaki K, Hisatsune K, Udoh K, Tanaka Y, Iijima Y, Takagi O (1998) J Mater Sci Mater Med 9:213CrossRefGoogle Scholar
  8. 8.
    Kim HI, Park YH, Lee HK, Seol HJ, Shiraishi T, Hisatsune K (2003) Dent Mater J 22:10CrossRefGoogle Scholar
  9. 9.
    Lee JH, Yi SJ, Seol HJ, Kwon YH, Lee JB, Kim HI (2006) J Alloys Compd 425:210CrossRefGoogle Scholar
  10. 10.
    Pan LG, Wang JN (2007) J Mater Sci Mater Med 18:171CrossRefGoogle Scholar
  11. 11.
    Cullity BD (1978) Elements of X-ray diffraction, 2nd edn. Addison-Wesley publishing Co, Inc, Massachusetts, p 506Google Scholar
  12. 12.
    Massalski TB (1990) Binary alloy phase diagrams, 2nd edn. ASM International, Materials Park, pp 12–13, 28–29, 358–362Google Scholar
  13. 13.
    Kim HI, Jang MI, Kim MS (1999) J Oral Rehabil 26:215CrossRefGoogle Scholar
  14. 14.
    Tanaka Y, Udoh K, Hisatsune K, Yasuda K (1994) Philos Mag A 69:925CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Mi-Gyoung Park
    • 1
  • Chin-Ho Yu
    • 1
  • Hyo-Joung Seol
    • 1
  • Yong Hoon Kwon
    • 1
  • Hyung-Il Kim
    • 1
    Email author
  1. 1.Department of Dental Materials, School of Dentistry and Medical Research InstitutePusan National UniversityPusanSouth Korea

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