Synergistic effect of pre-induced dislocations and ZrB2 on mechanical and thermal properties of Al/SiC composite

Abstract

Al/SiC composites are considered promising materials for electronic packaging and thermal management systems, because of their high strength, low CTE, and high thermal conductivity. Despite of promising characteristics, these composites often come at the cost of ductility. To address these issues, varying content of ZrB2 was incorporated in Al/3 wt% SiC composite to fabricate high performance hybrid composites via powder metallurgy. Subsequently, the microstructure evolution, thermophysical, and mechanical properties were investigated in a systematic way. The result shows that the pre-induced dislocations were characterized in Al/3 wt% SiC/0.5 wt% ZrB2 composite, which was further quantitatively estimated by XRD peak broadening analysis. The synergistic effect of pre-induced dislocations and grain refinement brought on by ZrB2 contributed to increase hardness, elongation to fracture, and thermal conductivity, significantly. Most specifically, the hardness, ultimate tensile strength (UTS), elongation to fracture, and ultimate compressive strength (UCS) of Al/3 wt% SiC/0.5 wt% ZrB2 composite were increased to 25.9 %, 33.0 %, 245.8 %, and 32.2 %, respectively, when compared to Al/3 wt% SiC composite. In addition, thermal conductivity was increased to 226.9 W/m.K (53.7 %) and coefficient of thermal expansion (CTE) was slightly decreased, while linear thermal expansion remained consistent in the temperature range of 25–200 °C. The thermophysical properties of hybrid Al/3 wt% SiC/0.5 wt% ZrB2 composite enhanced due to the high thermal conductivity of ZrB2, grain refinement, and stabilization effect of dislocations on the thermal expansion. Therefore, it can be stated that the addition of ZrB2 have a positive influence on the hardness, strength and elongation to fracture while maintaining high TC. These promising characteristics making them appealing materials for electronic packaging and thermal management systems.