Research On The Process Parameter,Microstructure And Properties Of Nickel-Based Superalloy Fabricated By Laser Additive Manufacture

Laser additive manufacturing technology is a new type of complex part preparation method.Due to its unique advantages,it can produce high-performance,complex structural parts,which has become a research hotspot in the manufacturing field in recent years.Therefore,this paper takes nickel-based alloy powder and GH3039 nickel-based superalloy wire as the research object,and carries out the research on the manufacturing process of coaxial powder feeding and the manufacturing technology of laser fuse additive.The metallographic microscope?OM?,X-ray diffractometer?XRD?,scanning electron microscope?SEM?,nanoindentation-hardness tester and other testing methods are used to prepare the coaxial powder feeding and laser fuse additive manufacturing technology.The single-pass single-layer sample was characterized by microstructure and performance,and then the influence of laser process parameters on macroscopic morphology and microstructure was analyzed,and the mathematical model of process parameters and macroscopic size parameters was established.The microhardness distribution of different parts of the cross section of the sedimentary layer was systematically analyzed.The specific research is as follows:?1?Based on the coaxial powder feeding technology,the process parameters and macroscopic dimensions,microstructure and microhardness were studied,and the relationship between macroscopic size,microstructure,microhardness and process parameters was obtained.The specific research contents are as follows:Through macroscopic dimension measurement,the effects of laser power,scanning speed and powder feeding speed on the macroscopic shape of the sedimentary layer are obtained,and the influence mechanism is revealed.Through the microstructure characterization test,the influence of process parameters on the morphology and size of different microstructures was obtained,and the influence mechanism was explained by the theory of solidification principle.Through the phase analysis results,it is found that the material structure prepared by the coaxial powder feeding additive manufacturing is mainly composed of?Ni and Ni3Fe.Finally,through the microhardness test,it is found that the microhardness of the cross section of the deposited layer gradually increases from the top to the bottom,which corresponds to the change of the structure.?2?Based on the laser fuse technology,we studied the process parameters and macroscopic dimensions,microstructure and microhardness,and obtained the relationship between macroscopic size,microstructure,microhardness and process parameters.The specific research contents are as follows:Through macroscopic dimension measurement and analysis,the effects of laser power,scanning speed and wire feeding speed on macroscopic morphology are obtained,and the mathematical model between macroscopic size parameters and combined process parameters is obtained by linear regression analysis.Through the microstructure analysis and analysis,it is found that the morphology and size of the microstructure change with the process parameters,and the influence mechanism is revealed by the theory of solidification theory.The phase analysis shows that the alloy obtained by the laser fuse process is mainly composed of?Fe,Ni?solid solution and Ni₃?Al,Ti?phase composition.The microhardness of the cross section of the sediment layer is also gradually rising from the top to the bottom.In a word,this paper systematically analyzes the technology of coaxial powder feeding and laser fuse additive manufacturing,and obtains the influence of process parameters on the macroscopic morphology,microstructure and microhardness of the deposited layer.Nickel-based superalloy process research has laid a certain foundation and has important guiding significance.?3?By comparing the two technologies,it is found that the coaxial powder feeding is less difficult,and the laser fuse can be formed within a certain wire feeding speed range due to the limitation of the wire feeding device;in addition,we find that for the coaxial sending The distribution of alloy morphology in powder and laser fuses is similar;however,there are different manifestations in defects.The samples prepared by coaxial powder feeding have the following three defects:holes,slag inclusions,cracks,and For laser fuses,there are mainly holes,cracks are not common,and slag inclusion is basically absent.