| Aluminum alloy is used as the composite matrix reinforced by particles,as common composite materials for aerospace,military and household use,have many advantages,such as high specific strength,wear resistance,corrosion resistance and excellent plasticity.In this paper,a multi-component and multi-scale Si Cp reinforced aluminum matrix composite was prepared by self-designed process,and the microstructure was designed to complete the preliminary macro-control.6000 series aluminum alloy with low strength but good ductility was used as the matrix.It was found that the content of particles,hot pressing process parameters and solid solution aging process had great influence on the material.The main research contents and conclusions are as follows:The effect of ball milling on the dispersion of tri-state and non tri-state powders and the effects of Si Cp content.The results show that the non tri-state powder reinforcements are uniformly dispersed around the matrix without agglomeration.The alloy powder added twice in the three state powder is effectively dispersed in the uniform mixture,and the trace elements appear a little agglomeration.The reinforcement and matrix particles with different contents are refined to a certain extent.In the process of extrusion,it is difficult to form and sinter when the particle content exceeds 25 vol%.The cold pressing pressure of 60 t is more uniform.When the sintering temperature is 700?,the hardness and density of the composite with 15vol% particle content are 115.7 HV and 96.7 %,respectively.The cold pressed material was hot extruded at 550?,and the oxidation degree of the material was controlled by copper cladding.The hot extrusion process improves the compactness of the material and eliminates the porosity and other defects.When the extrusion ratio is increased from 5 to 10,the average grain size decreases from 21?m to 16?m.The compressive strength,hardness and conductivity of the material are 740.48 MPa,244.48 HV and 21.45 % IACS respectively.When the extrusion ratio is 10,the grain size of the composites with different particle content is refined gradually with the increase of particle content because of the pinning effect.The best effect is when the particle content is 20 vol%.The fracture is mainly plastic fracture.After heat treatment,the compressive strength of the tri-state material reaches 735.74 MPa,and the hardness reaches 210.78 HV.When the reinforcement content increases,the plastic toughness increases and the intensity began to decline.The effect of solution aging on particle reinforced aluminum matrix composites was studied.It was found that the mechanical properties of the material reached the peak value after three groups of multi-stage solution.After G2 multi-stage solution treatment,the mechanical strength reached 680.42 MPa and the hardness reached 179.43 HV;the strength of the sample reached the peak value after 10?12h peak aging,and the mechanical properties began to decline with the increase of aging time.The compressive strength of the sample after T6-2 aging reached 721.48 MPa and the hardness is 185.82 HV.Finally,the best heat treatment process is G2 solution+T6-2 aging.In this paper,the microstructure and structure of 6000 series aluminum alloy with good plasticity were designed.The nano level Si Cp particles and Ti powder were added to adjust the strengthening and toughening effect of the reinforcement.The multi-component and multi-scale Si Cp/6061 Al composite was prepared by a new powder metallurgy process-new extrusion process-strengthening and toughening heat treatment process,and the macro-control of material properties was realized,which can enhance the strength of particles It provides scientific and technical basis for the composition design and control of strong aluminum matrix composites. |
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