Response surface optimization of milling parameters for synthesis of carbon nanotubes/Al5083 by powder metallurgy:

Carbon nanotube/Al5083 composite material has been synthesized by powder metallurgy. And the yield strength has been predicted by mathematical models. The parameters such as milling time, rotary speed and carbon nanotube concentration are considered independent variables. The experiments were carried out based on the central composite design. The experimental results were analyzed by the analysis of variance, which revealed that the quadratic model was statistically significant. And the optimal milling parameters were 104 min milling time, 798 r/min rotary speed and 2.95 wt% carbon nanotube concentration. Under these conditions, the predicted yield strength was 179 MPa. The quadratic equation model can also predict the maximum yield strength at different concentrations of carbon nanotubes. By comparing the predicted yield strength by the Orowan strengthening model and the coefficient of thermal expansion model, it was shown that the coefficient of thermal expansion model overestimated yield strength. And ...