摘要
Laser 3D printing based on melt growth has great potential in rapid preparation of Al_(2)O_(3)-based eutectic ce ramics.In this work,la rge-scale Al_(2)O_(3)/GdAlO_(3)/ZrO_(2)ternary eutectic ceramic rod with diameter of 4-5 mm and height higher than 250 mm was additively manufactured by laser directed energy deposition.Especially,heat treatment was applied to eliminate the microstructure heterogeneity in the as-deposited eutectic ceramic,and the microstructure homogenization mechanism was studied in depth.The results indicate that colonies and banded structures completely disappear after the heat treatment,producing a homogeneous network eutectic structure.The microstructure homogenization is revealed to experience three stages of discontinuous coarsening,continuous coarsening and microstructure coalescence.Additionally,it is found that the eutectic spacing linearly increases with the heat treatment time,meaning that the coarsening behavior of the laser 3D-printed Al_(2)O_(3)/GdAlO_(3)/ZrO_(2)eutectic ceramic satisfies well with the Graham-Kraft model.
基金
financially supported by the National Key R&D Program of China(Nos.2018YFB1106600 and 2017YFB1103500)
Science,Technology and Innovation Commission of Shenzhen Municipality(No.JCYJ20180306171121424)
National Natural Science Foundation of China(Nos.51822405,51472200)
Aeronautics Power Foundation(No.6141B09050337)
Key R&D Program of Shaan Xi Province(No.2018ZDCXL-GY-09-04)
Joint Research Funds of the Department of Science&Technology of Shaanxi Province and NPU(No.2020GXLH-Z-024)
Research Fund of the State Key Laboratory of Solidification Processing(NPU)(No.2019QZ-02)。
