Investigation On Process Optimization And Organization Analysis Of SiC Particles Reinforced Aluminum Matrix Composites By Selective Laser Melting

Selective laser melting technology is an advanced laser additive manufacturing technology based on the principle of dispersion and deposition.This technology manufactures components by accumulating "bottom up" materials,significantly shortening component manufacturing cycles,and reducing material and energy.The consumption increases the competitive advantage of the product.The technology does not require a mold.It has obvious advantages in terms of complex structure,individuation,and manufacturing of small-batch components.The manufactured parts have rapid solidification characteristics,high density,and can directly meet the requirements of use.Therefore,it has a wide range of applications in aerospace,medical,automotive and other fields.Metal matrix composites,because of their good mechanical properties,can meet industry's increasingly stringent requirements for material properties,and are receiving more and more attention.In particular,particle reinforced aluminum matrix composites have high specific strength and specific modulus.Low thermal expansion coefficient,high-temperature mechanical properties and fatigue resistance,wear resistance and other excellent performance,so the use of selective laser melting technology to prepare high quality and excellent performance of silicon carbide particle reinforced aluminum matrix composites has important practical significance.In this paper,the preparation process and process of forming SiCp reinforced aluminum matrix composites by selective laser melting technology were studied.The factors affecting the forming quality of the samples during the forming process were analyzed.The laser power,scanning speed,scanning pitch and other parameters were studied for SiCp reinforced aluminum matrix composites.The influence law of the density of material forming parts was analyzed.The change of phase composition,microstructure and microhardness of SiCp reinforced aluminum matrix composite specimens with different mass fractions were analyzed.The formation reasons of holes,cracks and other defects in the forming process were studied.The results of the study finally obtained optimized intervals for the SLM forming process of SiCp-reinforced Al-matrix composites with specific mass fractions.The results show that the optimized process area of SLM forming SiCp(10wt%)reinforced aluminum matrix composites is: laser power 290 W,scanning speed 800mm/s-1000mm/s,scanning pitch 0.12 mm,layer thickness 30?m,effective under the process parameters Reducing the generation of internal defects in materials,and obtaining high density and superior performance of SiCp reinforced aluminum matrix composites,especially when the scanning speed is 900mm/s,SiC particles have less influence on the melt flow in the molten pool,the molten pool has The stability is better and the viscosity is relatively low.Therefore,the SiC particles are distributed uniformly in the aluminum matrix,the interface is tightly bonded,only the pores with the smallest size exist in the sample,the density can reach about 98%,and the internal microscopy of the sample.Organizational uniformity has been significantly improved.Under the same process parameters,SiCp(20wt%)reinforced aluminum matrix composites have less aluminum melt formation,lower fluidity,higher viscosity in molten pool,and uneven distribution of SiC particles in the molten pool.The stability is poor,the surface of the molten pool has a significant spheroidizing effect,a large number of irregular sized holes occur between the layers,and the final sample forming quality is poor.There are Al phase,Si phase,SiC phase and Al4SiC4 phase in SLM forming SiC particle reinforced Al matrix composites with different mass fractions.The laser power is 290 W,the scanning speed is 900mm/s,and the SiCp(10wt%)is enhanced when the scanning pitch is 0.12 mm.Aluminum matrix composites have microhardness values between 200-230 HV0.1.In this paper,the selective melting technique was used to study the forming quality,microstructure and basic properties of SiCp(10wt%)and SiCp(20wt%)reinforced aluminum matrix composites with different process parameters.The SiCp reinforced aluminum matrix composites with specific mass fractions were obtained.In order to further improve the process and technological level of SLM forming SiCp reinforced aluminum matrix composites,the theoretical basis and research basis for further improving the interface bonding mechanism of SLM forming SiCp reinforced aluminum matrix composites and enhancing phase growth mechanism were optimized.