Creep Mechanism Determination on Dispersed Phase Amalgams using High Resolution Electron Microscopy (HRTEM) Observation

Abstract

Creep mechanism determination on dental amalgams has been a subject of interest in recent research works. Most of these studies conclude that the creep behavior can be explained by the well-known expression: ɛ = A σnexp (-Q/RT). Reported values for n (potential coefficient of stress) are in the order of 3 for phase dispersed dental amalgams and 2 for conventional amalgams. It suggests a grain sliding creep mechanism for conventional amalgams and a climb dislocation mechanism for creep in phase dispersed amalgams due to interactions with the dispersed CuxSny particles typical of this kind of amalgam(l). For both cases, the creep process occurs inside the γ (Ag2Hg3) phase matrix of low melting point (310 °K) which is slightly higher than typical mouth temperatures of about 400 °K (37 °C). In this work some microestructural evidences are obtained to support the behavior described above by using High Resolution Transmission Electron Microscopy (HRTEM).