Title: Study of the age-hardening in an Au-Cu-Ag dental alloy with Pt and Pd additions with dilatometry, hardness measurements and microstructural analysis

Authors: Barbara Rivolta, Maria Rosa Pinasco

Addresses: Department of Mechanical Engineering, Politecnico di Milano, Via La Masa, 1 20156, Milano, Italy. ' Department of Chemistry and Industrial Chemistry, University of Genova, Via Dodecaneso, 32 16046, Genova, Italy

Abstract: The age-hardening behaviour in a commercial gold dental alloy based on the Au-Cu-Ag system with platinum and palladium addition has been investigated with light optical microscope, scanning electron microscope, EDXS, image analysis, hardness measurements and dilatometric tests. The dilatometer, although seldom used in studying the hardening of precious alloys has proved useful to give good information on the heat treatment parameters. The most important hardening of the homogenised alloy takes place after isothermal treatments at temperatures between 150°C and 350°C. The metallographic analysis has shown that the microstructure is modified with the presence of discontinuous precipitation on the grain boundaries only after treatments at temperatures starting from 260°C.

Keywords: age hardening; dilatometry; gold alloys; dental alloys; microstructure; heat treatment; precipitation; Au-Cu-Ag system; scanning electron microscopy; SEM; energy dispersion X-rays system; EDXS; light optical microscopy; LOM; hardness; platinum; palladium; metallography.

DOI: 10.1504/IJMMP.2009.031401

International Journal of Microstructure and Materials Properties, 2009 Vol.4 No.4, pp.487 - 506

Published online: 02 Feb 2010 *

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