Hardening behavior after high-temperature solution treatment of Ag-20Pd-12Au-xCu alloys with different Cu contents for dental prosthetic restorations.
Ag-Pd-Au-Cu alloys have been used widely for dental prosthetic applications. Significant enhancement of the mechanical properties of the Ag-20Pd-12Au-14.5Cu alloy as a result of the precipitation of the β' phase through high-temperature solution treatment (ST), which is different from conventional aging treatment in these alloys, has been reported. The relationship between the unique hardening behavior and precipitation of the β' phase in Ag-20Pd-12Au-xCu alloys (x=6.5, 13, 14.5, 17, and 20mass%) subjected to the high-temperature ST at 1123K for 3.6ks was investigated in this study. Unique hardening behavior after the high-temperature ST also occurs in Ag-20Pd-12Au-xCu alloys (x=13, 17, and 20) with precipitation of the β' phase. However, hardening is not observed and the β' phase does not precipitate in the Ag-20Pd-12Au-6.5Cu alloy after the same ST. The tensile strength and 0.2% proof stress also increase in Ag-20Pd-12Au-xCu alloys (x=13, 14.5, 17, and 20) after the high-temperature ST. In addition, these values after the high-temperature ST increase with increasing Cu content in Ag-20Pd-12Au-xCu alloys (x=14.5, 17, and 20). The formation process of the β' phase can be explained in terms of diffusion of Ag and Cu atoms and precipitation of the β' phase. Clarification of the relationship between hardening and precipitation of the β' phase via high-temperature ST is expected to help the development of more effective heat treatments for hardening in Ag-20Pd-12Au-xCu alloys.
Department of Biomaterials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
Yonghwan
Y
Kim
Department of Biomaterials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan. Electronic address: niinomi@imr.tohoku.ac.jp.
Mitsuo
M
Niinomi
Department of Biomaterials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
Junko
J
Hieda
Department of Biomaterials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
Masaaki
M
Nakai
Department of Biomaterials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
Ken
K
Cho
Department of Dental Materials Science, School of Dentistry, Aichi-Gakuin University, Nagoya 464-0045, Japan.
Hisao
H
Fukui
D000497:Alloys / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D017266:Dental Prosthesis; D003799:Dental Stress Analysis / Q000379:methods*; D004058:Diffusion; D006046:Gold / Q000737:chemistry; D006244:Hardness; D006358:Hot Temperature; D008422:Materials Testing; D017348:Microscopy, Electron, Scanning Transmission; D013053:Spectrophotometry; D013314:Stress, Mechanical; D013718:Tensile Strength; D014961:X-Ray Diffraction; D014965:X-Rays
C120982:Ag-Pd-Cu-Au alloy; D000497:Alloys; D003722:Dental Alloys; D003764:Dental Materials; D006046:Gold; D003300:Copper
Dental Ag–20Pd–12Au–xCu alloys; Hardening; Heat treatment; L1(0)-type ordered β′ phase