Influence of temperature and dwelling time on low-cycle fatigue characteristic of isotropic conductive adhesive joint

The effects of temperature and dwell time on the low-cycle fatigue life of Ag-epoxy based conductive adhesive have been investigated by using a micro-joint specimen. The low cycle fatigue life of the conductive adhesive increases when test temperature is elevated beyond the glass transition point. On the other hand, the dwell time at 398 K reduces the fatigue life, which, however, is increased by the dwell time at 348 K. The cross-sectional image suggests the embrittlement of epoxy resin during the dwell time at 398 K, which reduces the fatigue endurance of the conductive adhesive. In contrast, some kind of recovery effects exists during dwell time near the glass transition temperature, which improves the fatigue life.