Processing, microstructure and mechanical properties of a novel mg matrix composites reinforced with urchin-like CNTs@SiCp

Abstract

A Mg6Zn composite reinforced by novel urchin-like hybrid reinforcement of carbon nanotubes and silicon carbide (CNTs@SiCp) was fabricated via semisolid stirring assisted with ultrasonic vibration method and exhibits remarkable strengthening effect. Carbon nanotubes (CNTs) were in-situ and dispersed uniformly in the matrix with the assistance of silicon carbide particle (SiCp) as “vehicle”. A series of synthesis parameters were optimized to produce high-quality CNTs. The graphitization degree and the yield of CNT were evaluated by Raman spectra and Thermogravimetric analysis (TGA), respectively. Compared with mono-SiCp reinforced Mg6Zn composite (SiCp/Mg-6Zn), the CNTs@SiCp reinforced Mg6Zn composite with urchin-like reinforcement (CNTs@SiCp/Mg-6Zn) enhanced the yield strength, ultimate tensile strength and elongation by 14%, 20% and 18.2% respectively. Digital image correlation (DIC) investigation indicates that the CNTs enhanced the interface bonding between SiCp and the Mg matrix. A SiC-(CNT-Mg)-Mg interface layer was formed between the SiCp and Mg matrix, which could relieve the interface stress concentration and impede microcrack propagation in the matrix under applied load. This work highlights the strengthening and toughening effects of the urchin-like CNTs@SiCp reinforcement and provides a new approach to fabricate hybrid composites.