Production of Al Metal Matrix Composites Reinforced with Carbon Nanotubes by Two-Stage Melt-Based HPDC-CE Method

Carbon nanotubes (CNTs) are well known as perfect reinforcement for high strength and lightweight composites due to their high specific strength, thermal, electrical, and mechanical characteristics. One of the important challenges is to obtain a homogeneous dispersion of CNTs in metal matrix, so development technologies for producing metal matrix composites (MMCs) is of great interest. Melting followed by solidification, may be successfully utilized for synthesizing CNT-reinforced aluminum-based MMCs. In this study, Al/CNT composites have been produced by direct injection of CNTs in pure aluminum using high-pressure die casting (HPDC) method. The as-produced billets were subjected to cyclic extrusion (CE) to refine CNT agglomerates and to increase CNT dispersion in aluminum. Current investigation demonstrates that more than 50% efficiency of combined HPDC-CE production method has been achieved. The resulting composites demonstrated improved mechanical properties.