Thermal cycling reliability of Al/50Sip composite for thermal management in electronic packaging

Excellent thermal fatigue resistance with long-term reliability is one of the key requirements for thermal management materials. The effect of thermal cycling on mechanical properties and degradation mechanism of Al/50 wt% Sip composite are investigated. The composite is fabricated by hot pressing of pre-alloyed powder, and thermally cycled between room temperature and various temperatures (200, 250, and 300 degrees C) for up to 800 cycles. The results show that mechanical properties of the composite are quite stable under the maximum heating temperature of 200 degrees C regardless of the number of thermal cycle. However, they decrease gradually under 250 and 300 degrees C with a greater number of thermal cycle. Microscopic observations indicate that the property degradation is mainly resulted from the fragmentation of Si particles owing to the thermal stress because of the coefficient of thermal expansion mismatch.