Effects of carbon nanotubes on the microstructure and mechanical properties of the wrought Mg-2.0Zn alloy

The effects of carbon nanotubes (CNTs) on the microstructure and mechanical properties of wrought Mg alloys with of 2.0 wt% of Zn content (Mg-2.0Zn) are investigated by the optical microscope (OM), transmission electron microscope (TEM), scanning electron microscope (SEM) and uniaxial tensile test. Different contents of CNTs are added separately in the as-cast ingots and as-extruded samples. The results showed that CNTs could greatly refine the microstructure of both as-cast alloy and as-extruded alloy. The tensile strength, yield strength, elongation and elasticity modulus of the alloy with CNTs were improved to different extents. Remarkably, the increase of elongation reached approximately 80%. The fracture surface of the alloy with CNTs mainly consisted of dimples with toughness rupture modes. Therefore, it suggests that CNTs could enhance the plasticity of wrought Mg-2.0Zn alloy without the reduction of strength.