A Novel Method to Fabricate CNT/Mg-6Zn Composites with High Strengthening Efficiency

A novel method was developed to fabricate carbon nanotubes (CNTs)-reinforced Mg matrix composites. The method consists of two steps: CNTs pre-dispersion by ball-milling and the ultrasonic melt processing. Mechanical ballmilling effectively pre-dispersed CNTs on Zn flakes with suitable rotational speed and ball-milling time. Serious CNT entanglements were dispersed by the ball-milling. However, ball-milling for a long time at high speed would damage the morphology of CNTs. The ultrasonic overcame the poor wettability between Mg melt and CNTs and then dispersed predispersed CNTs in the Mg melt. CNTs were distributed well in the composites and maintained integrated structure. CNTs significantly improved the mechanical properties of the matrix. The strengthening efficiency reached to 37.1, which proves the superiority of this novel method. Besides grain refinement, load transfer may make a great contribution to the improvement of the strength for the composites.