Process,Microstructure And Properties Of TiC_p/AlSi10Mg Composites By Laser Cladding Additive Manufacturing

In recent years,the industry has put forward new requirements for large-scale,complex and lightweight metal structural materials with the rapid development of aer ospace,new energy vehicles and shipbuilding industry.Particle reinforced aluminum matrix composites are widely used for their light weight,high specific strength,high specific stiffness,corrosion resistance,wear resistance and easy forming.Laser cladding technology can form large-scale complex components,which has the advantages of simple process,less process,low cost,short processing cycle and many kinds of machinable materials.Therefore,it has become a research focus in recent years that high performance particle reinforced aluminum matrix composites were prepared by laser cladding technology.In this paper,TiC_p/AlSi10Mg composites were prepared by laser cladding technology.The effects of the size and volume fraction of reinforcement phase on the microstructure and properties were studied.The optimum process parameters of heat treatment and the forming process of linear thin-walled parts and rotary thin-walled parts were studied.The single-pass cladding forming process of TiC_p/AlSi10Mg composites with different size and volume fraction of reinforcement phase was studied by single-pass deposition experiment.The effect of ceramic size and volume fraction on the density of the composites was analyzed.The study found that the pores in the composite deposition layer are mainly metallurgical pores.The more TiC content in the composite,the less metallurgical pores and the higher the density.The effect of fine TiC particles on the density is more obvious than that of coarse TiC particles.When the volume fraction of ceramic is 10%and the overlap ratio is 30%,the bulk deposition layer with dispersive distribution of ceramic particles,high density and best forming quality can be prepared.The higher the volume fraction of TiC,the higher microhardness.At the same volume fraction,the effect of fine TiC particles on the hardness and tensile properties of the composites is greater than that of coarse TiC particles.The results show that the ceramic particles are dispersed in the deposition layer corresponding to 10vol.%fine TiC,and the tensile property is the best.The tensile strength of scanning direction is the largest,reaching340.8MPa,and the elongation is 10.46%.The tensile strength in the deposition direction is the largest,reaching 298.6 MPa and the elongation is 6.83%.After T6 heat treatment,the strength and plasticity of TiC_p/AlSi10Mg composites are effectively improved.Heat treatment promotes spheroidization of eutectic Si and precipitation of Mg₂Si.The properties of the 10vol.%fine TiC composites can be effectively improved by solution treatment at 525?for 1h and aging treatment at 175?for 10h.The tensile strength of the composites in scanning direction and deposition direction is increased by 20.6%and 23.4%respectively,and the hardness is increased by 6.1%and 5.9%respectively.The tensile failure form of heat-treated composites is mainly ductile fracture.During the cladding process of linear thin-walled parts and rotary thin-walled parts,the defects such as oxidation,collapse,surface wrinkle and powder sticking are easy to arise.By optimizing the scanning path,alleviating the heat accumulation,controlling the lifting amount of single layer and adjusting the flow rate of protective gas,high-quality linear thin-walled parts and rotary thin-walled parts with smooth surface,high dimensional accuracy,no oxidation and collapse can be successfully prepared.