Research On The Enhancement Of Aluminum Alloy And Structure Lightening Technology Based On Selective Laser Melting

With the rapid development of aerospace,the demand for lighting components is increasing.The structure of most aerospace parts is complex,which is difficult to be processed by traditional manufacturing methods.As one of the emerging metal additive manufacturing methods,Selective Laser Melting(SLM)technology can form high-precision parts of arbitrary shapes.Aluminum alloy is widely used because of its low density and high specific strength.However,SLM formed aluminum alloy has the problems of insufficient strength(< 400 MPa)and low hardness.In this paper,rare-earth element Scandium(Sc)was added to Al Si10 Mg powder,and the process of SLM forming Al Si10 Mg samples and properties of samples were studied to prepare high performance aluminum alloy parts.On the other hand,a topology optimization method is used to lightweight the aircraft engine bracket from the structure of design,and the finite element simulation is used to verify.The main research contents of this paper are as follows:(1)The experimental study on SLM forming process of Al Si10 Mg was carried out,and optimize the process parameters(laser power and scanning speed)were optimized according to the density and section morphology of the samples.When the line energy density of the laser is 300 J/m(P=360 W,v=1200 mm/s),the sample section looks smooth without obvious pore defects.The density of the sample is as high as 96.78%.(2)Composite powder of 0.1wt%Sc-Al Si10 Mg and 0.5wt%Sc-Al Si10 Mg were prepared by ball milling.Under the optimized process parameters,phase analysis,microstructure observation and EBSD testing were performed on SLM shaped Sc-Al Si10 Mg samples.The results showed that the addition of Sc element could refine the grain size of Al Si10 Mg sample,and the average grain size changed from 2.7206 μm to 2.2347 μm,decreasing by 17.86%.(3)The effect of the addition of Scandium on the microhardness,tensile properties and corrosion resistance of SLM shaped Al Si10 Mg samples.The results showed that the microhardness of Al Si10 Mg samples increased and increased with the increase of Sc content.Microhardness changed from 146.89 HV to 174.88 HV,increasing by 19.06%.The tensile properties of the samples were significantly improved,and the ultimate tensile strength was changed from 370.20 MPa to 420.98 MPa,an increase of 13.72%.Elongation increased by 14.62% from 8.96% to 10.27%.The corrosion resistance of the samples was also improved,and the corrosion resistance of 0.1wt%Sc-Al Si10 Mg sample was slightly better than 0.5wt%Sc-Al Si10 Mg sample.(4)The structural lightweight design of GE aircraft engine bracket was carried out by topological software Inspire,and the static simulation verification of the topological model of the bracket was carried out by finite element software Workbench.The results showed that the topological reconstruction model could still meet the requirements of working conditions.Compared with the original design mass of 1235.3 g,the weight reduction reached 46.76%,and the lightweight effect was obvious.