Fabrication of a new Al-Al2O3-CNTs composite using friction stir processing (FSP)

A new Al-Al2O3-CNTs Composite has been successfully fabricated using friction stir processing. Uniform dispersion of nano-particles in the metal matrix was observed. Significant improvement in the micro-hardness and tensile strengths were obtained through the addition of nano particles. In particular the yield strength of the composites increased 70% compared with that of friction stir processed Al when both Al2O3 and CNTs were added in the matrix. The improvement in the mechanical properties is mainly attributed to grain refinement and Zener pinning effect caused by the addition of nano-sized particles. Al2O3 particles were observed at the bottom of the dimples at the fracture site, suggesting voids initiation at the Al/Al2O3 interfaces regions. The reinforcing mechanism with multiple nano-particles addition was discussed therein.