Preparation and properties of carbon nanotubes toughened Al-Mg alloy composite materials
Carbon nanotubes were selected as the reinforcing phase and a carbon nanotube toughened Al-Mg al-loy composite material was prepared by stirring casting method.The effects of the amount of carbon nanotubes added on the mechanical properties,microstructure and toughness of the composite materials were studied,and the toughening mechanism of carbon nanotubes on Al-Mg alloy was explored.The results showed that the addi-tion of an appropriate amount of carbon nanotubes refined the grain size of the Al-Mg alloy composite material,with a grain size of approximately 80 μm.When the addition amount of carbon nanotubes was 0.8 wt％,the fracture morphology of the composite material was the most uniform.As the amount of carbon nanotubes added increased,the tensile strength,elongation at break,and hardness of the composite material showed a trend of first increasing and then decreasing.When the addition amount of carbon nanotubes was 0.8 wt％,the tensile strength,elongation at break,and hardness all reach their maximum values,which were 208.6 MPa,15.8％and 53.1 HB,respectively.The addition of appropriate amount of carbon nanotubes significantly improves the toughness of Al-Mg alloy,gradually increasing the fracture elongation,prolonging the yield stage,and impro-ving the toughness.This is because an appropriate amount of carbon nanotubes can bind well with the alloy and penetrate the cracks of the alloy,exerting a bridging effect and hindering the initiation and propagation of cracks,thereby improving the-toughness of Al-Mg alloy composites,delaying the failure process of the alloy,and extending the yield stage of the alloy.Based on the above analysis,it can be concluded that the optimal ad-dition amount of carbon nanotubes is 0.8 wt％.
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