Technology Foundation Of Laser Engineered Net Shaping Of Al₂O₃-ZrO₂（Y₂O₃） Eutectic Ceramic

Y2O3) eutectic ceramic has excellent mechanical properties, corrosion resistance, oxidation resistance and high temperature stability, which has a great development potential at severe application environment in the fields of aerospace and marine chemistry industry. In recent years, laser engineered net shaping (LENSTM) technology has been put forward by Sandia National Laboratory, which is based on laser cladding and rapid prototyping. It could make raw material of powder directly formed into complex shapes of the three-dimensional entity parts. The technology has not only been taken away from traditional tool and mould, but also shortened the production period obviously. As a result, LENSTM has the advantage of direct forming high performance ceramic parts with complex shape, which plays an important role in the fields of key parts and components manufacturing in aerospace applications.Al2O3-ZrO2(Y2O3) eutectic ceramics forming experiments by LENS is presented in this paper. We have explored the law of forming quality of the ceramics with the change of laser power. Obtain the laser power range of good forming quality. Analyze the temperature and stress field of parts by the finite element method and reveal cracks formation and propagation mechanism. X-ray diffractometer, scanning electron microscopy and Vickers indenter was carried out on the sample phase composition analysis, micro structure observation, hardness and fracture toughness test. The main contents of the research are as follows:(1) Forming experiments are proceeded by LENS based on raw material of Al2O3-ZrO2(Y2O3) ceramic powder. Explored the influence of laser power on the forming quality of Al2O3-ZrO2(Y2O3) eutectic ceramic parts. Provided guidance for the optimization of laser power during forming process and for the improvement of forming quality of eutectic ceramic structure;(2) A LENSTM yielding Al2O3-ZrO2(Y2O3) ceramic thin-walled structure with25layers finite element model is established by ANSYS to Simulate the forming process of LENSTM. The results of temperature and stress field distribution during forming process are carried out to explain the formation rules of pores and cracks;(3) Eutectic and monotectic ceramic thin wall parts have been produced by varying the powder proportion. Observe the microstructure of parts with different compositions. Reveal the difference between microstructure of ceramic prepared by LENSTM and traditional method. Finally, evaluate the performance of the ceramic by relative density, Vickers hardness and fracture toughness test.In this paper, the method of LENSTM has been proposed to direct form Al2O3-ZrO2(Y2O3) eutectic ceramic with complex structures. We have preliminary explored the influence of laser power on the ceramic forming quality. The research will provide theoretical guidance and enlightenment for the further study. Analyze the characteristics of microstructure, hardness and fracture toughness of eutectics produced by LENSTM and highlight the advantages of LENSTM of eutectic ceramics.