Selective Laser Melting Forming Of AZ91D Magnesium Alloy Powder Process Research

Selective laser melting(SLM)is an addictive manufacturing technology which can directly manufacture metal parts.The technology is based on the principle of Layered superposition which can eliminate the restrictions of traditional processing methods on geometry.It also has a significant advantage in the preparation of complex structure.Magnesium is regarded as the lightest metal material in engineering applications,and widely used in transportation,electronic and communication engineering,aerospace,national military industry and many other fields.The study which used selective laser melting process to research magnesium is expected to enter the high-performance structure application field.In this research paper,we used AZ91 D magnesium powder as the raw material use and the selective laser melting process to carry out the forming experience.Firstly,the key problems which we might meet during the process such as serious vaporization phenomenon and poor combination with basic materials were solved.Then,we use the Orthogonal experimental design,range analysis and other ways to study the SLM process parameters and the influence and regularity of the mechanical properties.Then the specimens were treated by solid solution treatment.We also make a X ray diffraction and metallographic analysis,and obtained the optimized treatment.Finally,we would analyze the accuracy of specimens,propose the relevant methods to improve the accuracy of the specimens and prepare the forming partsThe results show that:(1)the optimization parameters of selective laser melting are as follows: laser power is 180 W,scanning speed is 500mm/s,scanning interval is 60?m.The scanning speed has the greatest influence on the density of the specimen,the laser power is inferior to it,and the scanning interval is the smallest.(2)the properties of the specimens prepared by the process parameters: the density of the specimen is 99.8%,the yielding strength is 200 Mpa,the tensile strength is 285 Mpa,elongation is 3.2%,Vickers hardness is 135 Hv.(3)the scheme of the specimen optimized is 420 ?* 12 h solid solution treatment.The process can greatly increase the elongation of the specimen to 5.9%.(4)the magnesium forming parts can be successfully prepared by using SLM process,and the horizontal direction precision can reach to 0.1mm,and the vertical direction precision can reach to 0.2mm.