Study On The Forming Processes And Properties Of Composite Powder Manufactured By Selective Laser Sintering

Composites have many good properties,such as high strength,high hardness,high temperature resistance,high corrosion resistance and good thermochemical stability,so they are widely applied in nuclear radiation protection,aerospace,biomedical and other fields.In view of the problems of long manufacturing cycle,high production cost and difficulty in manufacturing complex structural parts by traditional processing methods in the field of nuclear power radiation protection and structural ceramics,tungsten/nylon 12 radiation protection composite and alumina/epoxy resin ceramic composite are used as the main line in this paper,and the effect of SLS molding process parameters on the mechanical properties of the composite is studied by orthogonal experiment and range analysis method.At last,the shielding performance of the radiation protection composite was tested and the post-treatment process of alumina ceramic composite was studied.The main contents and achievements are as follows:(1)The preparation of tungsten powder/nylon 12 radiation protection composite powder and SLS molding optimization were studied.Based on the performance requirements of nuclear power radiation protection materials,W/PA2200 radiation protection composites were prepared by powder coating process,and the effect of W/PA2200 radiation protection composites in selective laser sintering with different mass ratio was compared and analyzed.At the same time,the preheating temperature of composites was determined to be 168 ? by single factor experimental analysis,and the effect of SLS molding process parameters on the tensile strength of tungsten powder/nylon 12 radiation protection composite was studied by orthogonal experimental method.The results show that the thickness of the powder layer has the greatest effect on the tensile strength of the sintered parts.The optimum technological parameters are: laser power is 20.4w,scanning speed is 3250mm/s,the thickness of the powder layer is 0.12 mm,and scanning distance is 0.14 mm.(2)The preparation of alumina/epoxy resin E12 ceramic composite and SLS molding process were studied.The alumina/epoxy resin E12 composite powder was made by mixing,choosing alumina powder with its size of 20?m and epoxy resin E12 powder accounting for 8% of composites powder in weight.In this paper,the SLS forming mechanism of alumina/epoxy E12 ceramic composite is discussed,and the influence of process parameters on the bending strength of SLS forming parts is analyzed by orthogonal experiment.The experimental results show that the best process parameters are as follows: laser power is 17.4W,scanning speed is 1800mm/s,scanning distance is 0.12 mm,powder layer thickness is 0.16 mm.(3)Shielding performance of radiation protection composites and post-treatment process of alumina ceramic composites were studied.The shielding rate of radiation protection composite is obtained by testing the shielding performance of SLS formed parts.Besides,the effect of different radiation protection composite on the shielding performance of ?-ray is analyzed.In this paper,the post-treatment of SLS formed parts of alumina ceramic composites is analyzed and studied,such as infiltration,degreasing and high temperature sintering process.It is found that the bending strength of SLS formed parts is greatly increased after post-treatment,which can meet the requirements of ceramic functional parts with complex structure with certain strength.