Microstructure and Mechanical Properties of AZ91 Alloy Composites Reinforced with Ni-Coated Carbon Nanotubes

AZ91 alloy composites reinforced with nickel coated carbon nanotubes(Ni-CNTs) were fabricated by stirring casting technology.The effects of carbon nanotubes on the mechanical properties and microstructure of the composites were studied,and the fractographs were observed and analyzed by scanning electron microscopy and energy spectrum analysis.The results show that the nickel coated CNTs could refine grain size of the matrix alloy and strengthen mechanical properties of the AZ91 magnesium alloy.Compared with the matrix alloy,tensile strength,elastic modulus and microhardness of the composites had been enhanced significantly with proper adding.The elongation and tensile strength were increased by 90.44% and 37.5% respectively.But with the excessive addition of Ni-CNTs,the Ni-CNTs would segragate,and mechanical properties of the composites were reduced.