The Study On The Preparation Of Closed-cell Aluminum Foam With Different Viscous Agents

Because of the effect on the performance of materials,pore structure is regarded as a defect,along with the improvement of understanding about the pore structure,the special features and structural property of pore structures were discovered gradually.Pore structures infiltrated into the nanomaterials,nonferrous metals,nonmetallic materials and other field.Closed-cell aluminum foam belongs to the pore structures materials,and because the low density and good crash energy dissipation ability and other properties,the closed-cell aluminum foam is widely used in machinery parts,hull materials,aeronautical materials.In this thesis,closed-cell aluminum foam was prepared by melt foaming method with different proportion of different viscous agents-Ca,Al₂O₃,SiC,the comparison of viscosity could be studied by macro-analysis and micro-analysis.On the one hand,pore size,porosity and density were used to characterize all the samples,the values of pore size and porosity of samples with SiC or Al₂O₃ are lower and there are some phenomena of aggregation and shrink on the distribution of pores.The result showed the viscous effect of Al₂O₃ and SiC did not work well.But the distribution of bubbles is uniform when the viscous agent is Ca,so the viscous effect of Ca was better.Finally,the best viscous agent and proportion were selected according to the requirements of the project.On the other hand,all samples were detected by XRD,then,the grain size was calculated by using of software Jade.The results showed the grain sizes of samples grew as the addition of SiC or Al₂O₃ increasing.But the grain sizes of samples showed a trend of first increase and then decrease as the addition of Ca increasing.In order to verify the result of XRD,all sample were characterized by metallographic microscope and the result in accordance with the XRD.A theoretical model constructed by the results of nucleation rate and the growth of grain,the defects and viscous effect was analyzed by the model.Additionally,partial sample?Al₂O₄-3.0wt%;SiC-1.0wt%;Ca-2.0wt%?is analyzed by SEM,then we studied the distribution of the viscous agent by morphology analysis of the pores and cell wall.The results showed that different viscous agents could influence the structure and stability of bubbles differently.Finally,to establish a pilot production line of closed-cell aluminum foam based on the further study.