Study On The Technology And Properties Of Go-Al Composites Fabricated By Laser Deposition Manufacturing

Graphene aluminum matrix composites have the advantages of fine corrosion resistance,light weight,fine strength and so on,have a good development trend and application prospect in aerospace and other fields.The traditional preparation technology has a series of problems,such as long production cycle,expensive manufacturing cost,low comprehensive utilization rate of materials and difficulty in manufacturing large complex structural parts.Laser deposition manufacturing technology is a new kind of processing technology that can directly transform from digital model to three-dimensional structural parts,which can overcome the shortcomings of traditional processing technology and provide an effective way for the preparation of graphene aluminum matrix composites with short cycle,low cost and high quality.In this paper,graphene oxide(GO)was selected as the reinforcing phase material and GOAlSi7Mg composite powder was prepared by the optimizing low temperature vacuum wet ball milling mixing process,the morphology and laser reflectivity of powder were studied.The GOAl composites were fabricated by laser deposition manufacturing(LDM)process,and the effects of laser power,scanning speed and powder feeding amount on the deposition layer were studied respectively.The technological parameters were optimized through orthogonal experiments.Pure AlSi7Mg aluminum alloy and the GO-Al composites with GO content of 0.05wt.%and 0.1 wt.%were prepared,respectively.The effects of GO content on microstructure and mechanical properties of composites were investigated,and the strengthening mechanism of GO reinforced aluminum alloy was further clarified.The composites were characterized by transmission electron microscope,Raman spectrum,optical microscope and diffuse reflectance spectrometer.The wet ball milling process can ensure the uniform dispersion of GO in the aluminum alloy matrix.With the increase of GO content,the laser reflectivity of composite powder decreased from 58.1%to 34.5%,the microstructure of the composite material was refined and the performance was improved.When the GO mass fraction was 0.1 wt.%,the Vickers hardness,tensile strength,elongation,elastic modulus and yield strength of the composites were 147.8HV,227.57MPa,6.41%,105.99GPa and 110.36MPa,respectively,which were 71.48%,51.7%,114.4%,37.1%and 53.8%higher than that of AlSi7Mg aluminum alloy matrix.