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Elucidation of Characteristic Strengthening Mechanisms in Dental Gold Alloys by High Resolution Electron Microscopy

Research Project

Project/Area Number 03452277
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 補綴理工系歯学
Research InstitutionNagasaki University

Principal Investigator

YASUDA Katsuhiro  Nagasaki Univ., Dent.Mater.Sci., Professor, 歯学部, 教授 (50013884)

Co-Investigator(Kenkyū-buntansha) BABA Kohmei  Technology Center of Nagaski, Senior Scientist, 研究員
TANAKA Yasuhiro  Nagasaki Univ., Dent.Mater.Sci., Research Associate, 歯学部, 助手 (10217086)
UDOH Koh-ichi  Nagasaki Univ., Dent.Mater.Sci., Research Associate, 歯学部, 助手 (60145266)
HISATSUNE Kunihiro  Nagasaki Univ., Dent.Mater.Sci., Associate Professor, 歯学部, 助教授 (20037526)
Project Period (FY) 1991 – 1993
Project Status Completed (Fiscal Year 1993)
Budget Amount *help
¥7,000,000 (Direct Cost: ¥7,000,000)
Fiscal Year 1993: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1992: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1991: ¥4,600,000 (Direct Cost: ¥4,600,000)
KeywordsGold Alloy / Phase Transformation / Age-hardening / Electron Microscopy / Electron and X-ray Diffraction / Order-Disorder Transformation / Spinodal Decomposition / Ordering Spinodal / AuCuーAg擬二元系合金 / 規則格子変態 / スピノ-ダル分解 / 歯科用金合金 / X線回析 / 制限視野電子回析 / 高分解能電子顕微鏡
Research Abstract

Age-hardening characteristics and associated phase transformations were studied by means of electrical resistivity measurements, hardness tests, X-ray and electron diffraction, transmission electron microscopy and scanning electron microscopic observations in an AuCu-14at.%Ag pseudobinary alloy. The critical temperature for ordering was determined to be 650 K and the spinodal temperature was estimated to be 640 K.Age-hardening at 623 K was attributed to nucleation and growth processes of the AuCu II' metastble ordered phase even though the ageing temperature was just below the spinodal temperature. While hardening in the lower temperature range took place at two stages, the former was due to spinodal decomposition and the latter was brought about by ordering of AuCu I' and/or AuCu II' metastable phases depending on ageing temperature.
The age-hardening mechanism of a commercial dental gold alloy containing platinum and palladium (Au-32at.%Cu-7.6at.%Ag-6.2at.%Zn-3.8at.%Pd-3.5at.%Pt) was also studied. The sequence of phase transformations during isothermal ageing below the critical temperature of ordering, Tc=825 K, was described as follows : disordered solid solution alpha_0 (fcc)--metastable AuCu I' ordered phase (fct) + metastable alpha_2' disordered phase (fcc)--equilibrium AuCu I ordered phase (fct) + equilibrium alpha_2 desordered phase (fcc). High resolution electron microscopic observation revealed that the hardening was due to the introduction of coherency strain at the interface between the AuCu I' ordered platelet and the surrounding matrix.
The spinodal ordering which was predicted by the CVM was confirmed by means of TEM, SAED and XRD examinations in the equiatomic AuCu alloy using direct ageing. The coherent phase boundary, Tc', and the spinodal ordering temperature, Ts, were identified from differences of microstructural features and changes in XRD patterns during ageing at verious temperatures. The Tc' and Ts were determined to be 648 K and 630 K.

Report

(4 results)
  • 1993 Annual Research Report   Final Research Report Summary
  • 1992 Annual Research Report
  • 1991 Annual Research Report
  • Research Products

    (25 results)

All Other

All Publications (25 results)

  • [Publications] Tani,T.: "Age-hardening Mechanisms in a Commercial Dental Gold Alloy Containing Platinum and Plladium" Journal of Dental Research. 70. 1350-1357 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Udoh,K.: "Microstructure of AuCu II in the disordered f.c.c.phase of AuCu-14at.%Ag alloy" Journal of Alloys and Compounds. 176. 147-158 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Hisatsune,K.: "Age-hardening characteristics in an AuCu-14at.%Ag alloy" Journal of Alloys and Compounds. 176. 269-283 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Udoh,K.: "Age-hardening associated with ordering and spinodal decomposition in a AgCu-40at.%Au pseudobinary alloy" Journal of Materials Science. 27. 504-510 (1992)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Hisatsune,K.: "Phase transformation behaviour of a low carat gold alloy for porcelain bonding during continuous heating" Journal of Materials Science:Materials in Medicine. 3. 54-58 (1992)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Yasuda,K.: "Characteristic Mosaic Texture related to Ordering in AuCu-9at.%Ag Pseudobinary Alloy" Dentistry in Japan. 29. 91-102 (1992)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Tani, T.: "Age-hardening Mechanisms in a Commercial Dental Alloy Containing Platinum and Palladium" Journal of Dental Research. 70. 1350-1357 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Udoh, K.: "Microstructure of AuCu II in the disordered f.c.c.phase of AuCu-14at.%Ag alloy" Journal of Alloys and Compounds. 176. 147-158 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Hisatsune, K.: "Age-hardening characteristics in an AuCu-14at.%Ag alloy" Journal of Alloys and Compounds. 176. 269-283 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Udoh, K.: "Age-hardening associated with ordering and spinodal decomposition in a AgCu-40at.%Au pseudobinary alloy" Journal of Materials Science. 27. 504-510 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Hisatsune, K.: "Phase transformation behavior of a low carat gold alloy for porcelain bonding during continuous heating" Journal of Materials Science : Materials in Medicine. 3. 54-58 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Yasuda, K: "Characteristic Mosaic Texture related to Ordering in AuCu-9at.%Ag Pseudobinary Alloy" Dentistry in Japan. 29. 91-102 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Tani,T.: "Age-hardening Mechanisms in a Commercial Dental Gold Alloy ContainingPlatinum and Palladium" Journal of Dental Research. 70. 1350-1357 (1991)

    • Related Report
      1993 Annual Research Report
  • [Publications] Udoh,K.: "Microstructure of AuCu II in the disordered f.c.c.phase of AuCu-14at.%Ag allov" Journal of Alloys and Compounds. 176. 147-158 (1991)

    • Related Report
      1993 Annual Research Report
  • [Publications] Hisatsune,K.: "Age-hardening characteristics in an AuCu-14at.%Ag alloy" Journal of Alloys and Compounds. 176. 269-283 (1991)

    • Related Report
      1993 Annual Research Report
  • [Publications] Udoh,K.: "Age-hardening associated with ordering and spinocal decomposition in a AgCu-40at.%Au pseudobinary alloy" Journal of Materials Science. 27. 504-510 (1992)

    • Related Report
      1993 Annual Research Report
  • [Publications] Hisatsune,K.: "Phase transformation behaviour of a low carat gold alloy for porcelain bonding during continuous heating" Journal of Materials Science:Materials in Madicine. 3. 54-58 (1992)

    • Related Report
      1993 Annual Research Report
  • [Publications] Yasuda,K.: "Characteristic Mosaic Texture Related to Ordering in AuCu-9at.%Ag Pseudobinary Alloy" Dentistry in Japan. 29. 91-102 (1992)

    • Related Report
      1993 Annual Research Report
  • [Publications] K.Hisatsune,et al.,: "Phase Transformation Behaviour of a Low Carat Gold Alloy for Porcelain Bonding during Continuous Heating." Jornal of Materials Science: Materials in Medicine,. 3. 54-58 (1992)

    • Related Report
      1992 Annual Research Report
  • [Publications] K.Udoh,et al.,: "Age-hardening associated with ordering and spinodal decomposition in a AgCu-40at.%Au alloy." Journal of Materials Science,. 27. 504-510 (1992)

    • Related Report
      1992 Annual Research Report
  • [Publications] K.yasuda,et al.,: "Characteristic Mosaic Texture Related to Ordering in AuCu-9at.%Ag Pseudobinary Alloy." Dentistry in Japan. 29. 91-102 (1992)

    • Related Report
      1992 Annual Research Report
  • [Publications] K.Udoh,H.Fujiyama,K.Hisatsune,M.Hasaka and K.Yasuda: "Ageーhardening associated with ordering and spinodal decomposition in a AgCuー40at.%Au pseudobinary alloy" Journal of Materials Science. 27. 504-510 (1992)

    • Related Report
      1991 Annual Research Report
  • [Publications] K.Hisatsune,Y.Tanaka,T.Tani,K.Udoh and K.Yasuda: "Phase transformation behaviour of a low carat gold alloy for porcelain bonding during continuous heating" Journal of Materials Science;Materials in Medicine. 3. 54-58 (1992)

    • Related Report
      1991 Annual Research Report
  • [Publications] K.Hisatsune,Y.Tanaka,K.Udon and K.Yasuda: "Effect of the Current in Determing a Critical Temperature by Electrical Resistivity Measurements" to be published in Scripta Metallurgica et Materialia.

    • Related Report
      1991 Annual Research Report
  • [Publications] Y.Tanaka,K.Udoh,K.Hisatsune and K.Yasuda: "Ordering Processes in the Vicinity of Spinodal Ordering Temperature of Stoichiometric AuCu Alloy" to be published in Philosophical Magazine.

    • Related Report
      1991 Annual Research Report

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Published: 1991-04-01   Modified: 2016-04-21  

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