Effects of Casting Defects and Microstructure on Fatigue Properties of Cast Ag-Pd-Cu-Au-Zn Alloy for Dental Applications

Mizumoto, Toshio; Niinomi, Mitsuo; Akahori, Toshikazu; Fukui, Hisao

doi:10.4028/www.scientific.net/msf.426-432.3207

Cited by 2 publications

(1 citation statement)

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“…Dental alloys have been designed by selecting elements according to primary purpose. Ag-Pd-Cu-Au system alloy, which was one of representative commercial dental silver type alloys [1][2][3][4][5][6][7][8], shows the unique hardening mechanism after a simple solution treatment (ST) at relatively high temperature. It has been reported that the mechanical strength of Ag-20-Pd-14.5Cu-12Au alloy (S12) is enhanced by a solution treatment (ST) at temperature higher than 1073 K followed by water quenching without being subjected to aging treatment.…”

Section: Introductionmentioning

confidence: 99%

Relationship between Microstructure and Mechanical Strength of Dental Semiprecious Alloys Subjected to Solution Treatment

Akahori

Mizuno

Niinomi

et al. 2018

MSF

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Silver alloy is one of semi-precious alloys for dental prosthesis, which has been applied remarkably in Japanese dental field. Ag-20Pd-17.7Cu-12Au alloy (G12), which was newly developed for commercial dental silver alloy, shows the unique hardening mechanism after a simple solution treatment (ST) at relatively high temperature. However, the relationship between ST at various temperature and the mechanical strength of G12 has not been investigated fully. Therefore, the relationship between ST and mechanical properties of G12 after ST at various temperatures was investigated systematically in this study. G12 subjected to ST at relatively high temperature of 1173 K is composed of three kinds of phases with Ag-rich α2 phase, Cu-rich α1 phase and β phase of Pd-Cu intermetallic compound. Although nominal melting point of G12 was around 1233 K, the high Cu concentration area like α1 phase was partially dissolved and then the α1, α2 and partial β phases re-precipitated during cooling. On the other hand, the microstructure of G12 aged at 673 K after ST at 1023 K (STA) was mainly composed of two kinds of phases with α2 and α1 phases with a small amount of β phase, which was a typical microstructure of STA. The Vickers hardness of G12 subjected to ST at 1173 K was identical to that of the same alloy subjected to STA although the tensile strength, fatigue limit and ductility deteriorated to some degrees. The corrosion potential of G12 changed drastically with the temperature of ST. The potential may have been increased by the decrease in the volume fraction of the α1 phase with relatively high Cu content.

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Section: Introductionmentioning

confidence: 99%

Relationship between Microstructure and Mechanical Strength of Dental Semiprecious Alloys Subjected to Solution Treatment

Akahori

Mizuno

Niinomi

et al. 2018

MSF

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Fatigue limits and SEM/TEM observations of fracture characteristics for three Pd—Ag dental casting alloys

Brantley

Guo

et al. 2007

J Mater Sci: Mater Med

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The fatigue limits and fracture characteristics for three Pd-Ag dental casting alloys (Super Star, Heraeus Kulzer; Rx 91, Pentron; W-1, Ivoclar Vivadent) were studied. Specimens meeting the dimensions for ADA Specifications No. 5 and 38, and having the as-cast surface condition, were subjected to heat treatment simulating dental porcelain firing cycles and fatigued in air at room temperature under uniaxial tension-compression at 10 Hz. A ratio of compressive stress amplitude to tensile stress amplitude (R-ratio) of -1 was used. Alloy microstructures and fracture surfaces were examined with a scanning electron microscope and a transmission electron microscope. Fatigue limits for the three alloys had low values of approximately 15% of the yield strength for 0.2% permanent tensile strain. Complex fracture surfaces with characteristic striations were observed for all three fatigued alloys. Planar slip of dislocations occurred in the Pd solid solution matrix, along with dislocation-precipitate interactions and dislocation networks in the interfaces between the precipitates and surrounding matrix. Twinning occurred in the Pd solid solution matrix of Rx 91, and within discontinuous precipitates in Super Star and Rx 91. The low fatigue limits for these alloys are attributed to their complex microstructures and perhaps to casting defects.

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Effects of Casting Defects and Microstructure on Fatigue Properties of Cast Ag-Pd-Cu-Au-Zn Alloy for Dental Applications

Cited by 2 publications

References 0 publications

Relationship between Microstructure and Mechanical Strength of Dental Semiprecious Alloys Subjected to Solution Treatment

Relationship between Microstructure and Mechanical Strength of Dental Semiprecious Alloys Subjected to Solution Treatment

Fatigue limits and SEM/TEM observations of fracture characteristics for three Pd—Ag dental casting alloys

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