Investigation On The Process Of Wire Arc Additive Manufacturing Of High Strength Aluminum Alloy

High strength aluminium alloys have been widely applied to aerospace,vehicles,weapons,equipment and other fields due to its many excellent properties such as low density,high strength rate and corrosion-resistant.However,Therefore,the disadvantages such as long production cycle and low material utilization of traditional process manners(forging and casting)in manufacturing high strength aluminium alloy limit the development of the application of high strength aluminium alloy.Additve manufacturing can solve the problem above.So the research of high performance aluminum alloy material additive manufacturing technology has broad application prospects.However,coMPared with titanium alloy,coares grains and defects hamperd the application of aluminum alloy additive manufacturing.To solve the above problems,this paper according to the arc material manufacturing related basic theory,design parameters to explore test,studied the influence of process parameters on forming quality and forming characteristics and forming performance of the samples are analyzed,and effective to eliminate the defects.But also found that the arc increases the material system of coarse grains problems that cannot be solved effectively,so in this article,by means of friction stir processing to post-processing of arc added material manufacturing samples,make the grains are refined obviously.In the end,the aluminum alloy arc additive manufacturing sample was obtained,which was tiny and the density was 99%.The main results are as follows:(1)With the pulse frequency increases,the surfaces of the samples get smoother,but the ac current has less effect on the surface.At the same time,with the ac current and the pulse frequency increase,the width of the sample increase,but the layer thickness decreases.The pulse frequency and the ac current can obviously influence the microstructure of the sample.As the pulse frequency and the alternating current increase,the grain shape gradually becomes the column grains from equiaxed grains and the grain size gradually increases.(2)As the pulse frequency increases,the density of the sample is a tendency to decrease after a first rise,and the resulting density is 99 percent when the pulse frequency is 50 Hz.Much more larger pores can be found at the high pulse frequency and more smaller pores will be found at the low pulse frequency.(3)Both the pulse frequency and the ac current will have a noticeable effect on the mechanical properties of arc additive manufacturing aluminium alloy.With the increase of pulse frequency and ac current,the mechanical properties of the samples are decreased,and the form of the fracture modes of the arc additive manufacturing aluminium alloy is plastic fracture.(4)The grain of the sample was obviously refined after friction stir process,and the degree of refinement was different in different stirring areas.In this case,the mixing friction core area and the shaft shoulder area are more obvious than the heat affected area.The moving speed and the increase of the speed increase the mechanical properties of the sample after the friction.In the process parameters,the mechanical performance of 100mm/min with speed 1000r/min is optimal.The tensile strength reached 475 MPa,with an elongation rate of 13.5%,exceeding the mechanical properties of the standard.