Research On The Preparations And Properties Of Carbon Nanotubes Reinforced Aluminum Matrix Composites

Carbon nanotubes were widely concerned as it is one of the one-dimensional carbon materials which have superb properties such as mechanics, electricity and thermal. It is also possesses high intensity and modulus characteristics as superior wild phase of composite. By using carbon nanotubes to reinforce aluminum matrix composite and exploit the methods of composite manufacturing as well as research on its other relative properties. It has significant value and meaning to deep research on how carbon nanotubes improve the properties of aluminum matrix composite.It is proved that by using powder hot-rolling to manufacture carbon nanotubes reinforced aluminum matrix composites from this article. Taking advantage of continuous hot-rolling to avoid the shortage of slack during the process of traditional powder metallurgy, which can accomplish composite continuous molding. Moreover, it also researches the influence of content of carbon nanotubes, milling duration between the structure and composite powder, revolving speed and sinter point on carbon nanotubes reinforced aluminum matrix composites.The research result has shown that rolling can reduce the interval in between the internals of composite and grain orientation of aluminum matrix, which accomplish the carbon nanotubes located uniformly in aluminum matrix. With the increasing numbers of carbon naaotubes, the density and the relative densities are dropped. However, both tensile strength and hardness of composite rose at the beginning then dropped later. Its tensile strength and hardness reaches peak value (298.23MPa,93.33HB) when the content of carbon nanotubes reaches 1.5%. Comparing to pure aluminum matrix which manufactured in the same process, the figures were increased 33.4% and 15.4%. The thermal expansion coefficient of composite will be increased gradually since the temperature goes higher so that thermal diffusion coefficient will be decreased gradually as well. In the specific circumstance when temperature reaches 200 ? and carbon nanotubes has 2%, the composite thermal expansion coefficient is 17.84×10-6 K which has decreased 17.14% if comparing to aluminium matrix. While thermal expansion coefficient will be at 37.036 mm2/s which has deceased 14.39% if comparing with aluminium.Using the combination processes of milling-in advance carbon nanotubes and powder metallurgy to produce carbon nanotubes reinforced aluminum matrix composites. Researching the influence of different ball-milling ratio and duration about carbon nanotubes' length-diameter ratio on composite. The research found that there has dispersive effect when milling- in advance for carbon nanotubes. With the milling time getting longer, the tensile strength and hardness are all firstly go higher but then drop down. As milling time goes to 150 minutes, the tensile strength is 243.35 MPa while hardness is 82.70 HB. When the the rotation speed of milling- in advance carbon nanotubes goes to 400r/min, the tensile strength will be reach 279.73 MPa which has the best effect on strength composited and hardness can reach 78.64 HB.