Thermal Conductivity of Hot-Rolled Al7075/TiB2/Graphite Hybrid MMCs

This study focuses on the impact of graphite (Gr) and titanium diboride (TiB2) hybrid reinforcement on the thermal conductivity of hybrid composite Al7075. Using liquid metallurgy, hybrid composites with two distinct reinforcements were synthesised. The formed hybrid composites were treated with hot rolling at 400 °C with a reduction ratio of 50%. Under hot-rolled and as-cast conditions, the effects of heat treatment and hybrid reinforcement on thermal conductivity and microstructure were investigated. The thermal conductivity of the hybrid composites was determined using the ASTM E1530 standard test protocol. The microstructure analysis of composites revealed a reasonably uniform dispersion of Gr particles and titanium diboride. The investigation of hybrid composites revealed that the reinforced particles and matrix formed an exceptional bond. The thermal conductivity of the cast and hot-rolled hybrid composites is reduced by 14.72 and 19.31%, respectively, compared to the unreinforced alloy. After heat treatment, the thermal conductivity of cast and rolled Al7075/25wt%TiB2/8wt%Gr hybrid composites increased by 4.54 and 1.7%, respectively.