title: Age-hardening behaviour and microstructure of a silver alloy with high Cu content for dental application.
abstract: Age-hardening behaviour and the related microstructural changes of a silver alloy with relatively high Cu content were elucidated by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). The microstructure of the solution-treated specimen was composed of the Ag-rich matrix, the Cu-rich particle-like structures containing Pd, and the lamellar structure of both phases. By the age-hardening heat-treatment, the Cu element began to precipitate from the Ag-rich matrix by the solubility limit, and the very fine Cu-rich precipitates became coarsened by further aging. The silver alloy with relatively high Cu content showed apparent age-hardenability. The hardness of the solution-treated specimen began to increase and reached a maximum value with increasing aging time, and then the hardness decreased gradually after maintaining the maximum value for short periods of time. The early stage of precipitation of the Cu-rich phase from the Ag-rich matrix seemed to have caused the increase in hardness. The decrease in hardness was attributed to the coarsening of the Cu-rich precipitates in the later stage of the age-hardening process.
authors.affiliation: Department of Dental Materials, College of Dentistry, Pusan National University, 1-10 Ami-dong, Seo-gu, Pusan 602-739, South Korea.
authors.forename: Hyo-Joung
authors.initials: HJ
authors.lastname: Seol
authors.forename: Young-Gu
authors.initials: YG
authors.lastname: Park
authors.forename: Yong
authors.initials: Y
authors.lastname: Hoon Kwon
authors.forename: Yukyo
authors.initials: Y
authors.lastname: Takada
authors.forename: Hyung-Il
authors.initials: HI
authors.lastname: Kim
mesh_terms: D003300:Copper; D003722:Dental Alloys / Q000737:chemistry*; D003735:Dental Casting Technique; D004577:Electron Probe Microanalysis; D006245:Hardness Tests; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D012834:Silver; D013499:Surface Properties; D013997:Time Factors; D014961:X-Ray Diffraction
chemical_list: D003722:Dental Alloys; D012834:Silver; D003300:Copper