Abstract
In this study, we report the fabrication of high-strength aluminum (Al) matrix composites (AMCs) reinforced with in situ formed Al_4C_3 nanorods up to about 16 wt.%. Different contents (1,2 and 4 wt.%) of carbon nanotubes (CNTs) were used as the starting materials for the template reaction with Al matrix. Al-CNT powder mixtures were dispersed by a high energy ball milling process and then consolidated by spark plasma sintering and subsequent hot-extrusion. The microstructural and mechanical properties of Al_4C_3-reinforced composites were characterized. With 1 and 2 wt.% CNTs, homogeneous CNT dispersion was achieved and resulted in singly distributed 4 and 8 wt.% Al_4C_3 nanorods, respectively. However, with 4 wt.% CNTs, there existed CNT agglomerations in the powder mixture and it led to remained CNTs in the composite reinforced with about 16 wt.% Al_4C_3. Consequently, AMCs containing 8 wt.% Al_4C_3 showed highest tensile strength.
