Al₂O₃-YAG共晶陶瓷材料以其出色的高温强度、抗氧化性、高温结构稳定性成为航空航天领域高温合金的理想替代材料。本文采用激光近净成形技术，分别在普通基底、水冷恒温基底上进行了Al₂O₃-YAG共晶陶瓷薄壁件成形实验，得到了不同基底上成形的薄壁样件，比较了两者的微观组织及显微硬度差异。结果表明，采用普通基底成形的薄壁件微观组织呈三维网状结构，平均共晶间距为0.96 μm；采用水冷恒温基底后，薄壁顶部微观组织形貌呈晶团结构，薄壁底部呈枝状晶结构，微观组织逆热流方向生长特性明显，平均共晶间距减小至0.21 μm；和普通基底上成形的Al₂O₃-YAG共晶陶瓷薄壁件显微硬度相比，使用水冷恒温基底成形的Al₂O₃-YAG共晶陶瓷薄壁件硬度提高约10%.

Al₂O₃-YAG eutectic ceramic has become an ideal alternative to high-temperature alloys because of its excellent high temperature strength, high oxidation resistance and high temperature structural stability. The technology of laser engineered net shaping was used to prepare the Al₂O₃-YAG eutectic ceramic thin-wall sam-ples. These samples were prepared on a common substrate and a water-cooled constant temperature substrate respectively. Their microstructure and microhardness were compared. The results show that the microstructure of thin-wall sample prepared on the common substrate is three-dimensional network structure with an average eu-tectic spacing of 0.96 μm. And the microstructure of top part of the sample prepared on the water-cooled constant temperature substrate is colony structure, while the microstructure of bottom part is dendrite structure which grows in the reverse direction of the heat flow. The average eutectic spacing of samples prepared on the wa-ter-cooled substrate has reduced to 0.21 μm. Compared with the microhardness of two kinds of thin-wall sam-ples prepared on the different substrates, it is found that the microhardness of the thin–wall samples prepared on the water-cooled constant temperature substrate is increased by about 10%.