Fatigue properties of cast Ag-Pd-Cu-Au-Zn alloy for dental applications in the relation with casting defects

Toshio Mizumoto, Mitsuo Niinomi, Yoshiki Nakano, Toshikazu Akahori, Hisao Fukui

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Ag-Pd-Cu-Au-Zn type alloys have been widely used as dental prosthetic materials. In general, the dental prosthetic products are fabricated by a dental casting method. The dental castings contain the casting defects such as micro shrinkages, pores, surface roughness, etc. Cyclic stress, that is, fatigue stress due to the mastification is applied to the dental prosthesis in the practical use. Therefore, the effects of the casting defects such as micro shrinkages, pores and surface roughness on the fatigue properties of the cast Ag-Pd-Cu-Au-Zn type alloy were investigated in the comparison with the fatigue properties of the drawn Ag-Pd-Cu-Au-Zn alloy in this study. Fatigue tests of Ag-Pd-Cu-Au-Zn alloy cast using a dental casting machine were carried out, and then the fatigue properties of the cast alloy were investigated in the relation with casting defects. The fatigue strength of the cast Ag-Pd-Cu-Au-Zn alloy is considerably smaller than that of the drawn Ag-Pd-Cu-Au-Zn alloy. The fatigue crack of the cast alloy initiates preferentially at the shrinkage near the specimen surface. The scatter of the fatigue strength of the cast alloy becomes to be small by relating the fatigue life with the maximum stress intensity factor calculated assuming the shrinkage that becomes to be a fatigue crack initiation site as a initial crack. This means that the size of the shrinkage affects the fatigue strength of this cast alloy strongly. The tolerant size of the shrinkage that satisfies the target value of the fatigue limit (230 MPa) of this cast alloy is calculated to be below 80 μm using the equation derived in this study, which describes the relationship between the maximum stress intensity factor and the number of the cycles to failure.

Original languageEnglish
Pages (from-to)3160-3166
Number of pages7
JournalMaterials Transactions
Volume43
Issue number12
DOIs
Publication statusPublished - 2002 Dec

Keywords

  • Casting defects
  • Dental casting
  • Dental material
  • Fatigue property
  • Pore
  • Shrinkage
  • Silver-palladium-copper-gold-zinc type alloy
  • Surface roughness

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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