%0 Journal Article %T Age-hardenability and related microstructural changes during and after phase transformation in an Au-Ag-Cu-based dental alloy %A Kim %A Hyung-Il %A Kim %A Tae-Wan %A Kim %A Young-Oh %A Cho %A Su-Yeon %A Lee %A Gwang-Young %A Kwon %A Yong Hoon %A Seol %A Hyo-Joung %J Materials Research %D 2013 %I ABM, ABC, ABPol, SBCC, SBCr, SBMM, SBPMat %R 10.1590/S1516-14392012005000169 %X the aim of this study was to clarify how the microstructural changes during and after phase transformation determine the age-hardenability of an au-ag-cu-based dental alloy. the rapid increase in hardness in the initial stage was the result of rapid atomic diffusion by spinodal decomposition into metastable ag-rich' and cu-rich' phases. the constant hardening after apparent initial hardening was the result of a subsequent transformation of the metastable ag-rich' and cu-rich' phases to the stable ag-rich ¦Á1phase and aucu i phase through the metastable aucu i' phase. during the increase in hardness, fine block-like structure with high coherency formed in the grain interior, which changed to a fine cross-hatched structure. a relatively coarse lamellar structure composed of ag-rich ¦Á1and aucu i phases grew from the grain boundaries, initiating softening before the grain interior reached its maximum hardness. as a result, the spinodal decomposition attributed to rapid hardening by forming the fine block-like structure, and the subsequent ordering into aucu i, which is a famous hardening mechanism, weakened its hardening effect by accelerating the lamellar-forming grain boundary reaction. %K spinodal decomposition %K metastable phase %K age-hardening %K lamellar-forming grain boundary reaction. %U http://www.scielo.br/scielo.php?script=sci_abstract&pid=S1516-14392013000100009&lng=en&nrm=iso&tlng=en