激光增材制造超高温氧化物共晶陶瓷研究进展

超高温氧化物共晶陶瓷具有优异的高温强度、高温蠕变性能、高温结构稳定性以及良好的高温抗氧化和抗腐蚀性能, 成为1400 ℃以上高温氧化环境下长期服役的新型候选超高温结构材料之一, 在新一代航空航天高端装备热结构部件中具有重要的应用前景。基于熔体生长技术, 以选择性激光熔化和激光定性能量沉积为代表的激光增材制造技术具有一步快速近净成形大尺寸、复杂形状构件的独特优势, 近年来已发展成为制备高性能氧化物共晶陶瓷最具潜力的前沿技术。本文从工作原理、成形特点、技术分类等方面概述了基于熔体生长的两种典型激光增材制造技术, 综述了激光增材制造技术在超高温氧化物共晶陶瓷制备领域的研究现状和特点优势, 重点介绍了选择性激光熔化和激光定向能量沉积超高温氧化物共晶陶瓷在激光成形工艺、凝固缺陷控制、凝固组织演化、力学性能等方面的研究进展。最后, 指出了实现氧化物共晶陶瓷激光增材制造工程化应用亟需突破的关键瓶颈, 并对该领域未来的重点发展方向进行了展望。

Research Progress on Ultrahigh Temperature Oxide Eutectic Ceramics by Laser Additive Manufacturing

Melt-grown oxide eutectic ceramics possess a large area of clean and firmly bonded phase interfaces through liquid-solid phase transformation, which makes them present excellent high-temperature properties such as strength retention, creep resistance, thermal stability, oxidation and corrosion resistance. As a result, directionally solidified oxide eutectic composite ceramics have been regarded as one of candidates for new generation of high temperature structural materials which can service above 1400 ℃ in oxidation environment for a long period. In recent years, laser additive manufacturing based on melt growth has developed into the most promising technique for preparing ultrahigh-temperature oxide eutectic ceramics due to its unique advantage in one-step fabricating highly dense parts with large sample size and complex shape. In this paper, laser additive manufacturing technology was summarized in terms of forming principle, technical features and classification. The research status and the encountered technical problems in additively manufacturing melt-grown oxide eutectic ceramics were reviewed. Moreover, the research progress on laser additive manufacturing oxide eutectic ceramics was introduced from the aspects of laser forming process, solidification defect control, solidification microstructure evolution, and mechanical properties. Finally, the key bottlenecks of realizing engineering applications of the laser 3D-printed oxide eutectic ceramics were pointed out, and the future development directions of this field were prospected. The focus of the future work can be summarized into four points: developing high-quality spherical eutectic ceramic powders, preparing large-scale eutectic parts with complex shapes, accurate controlling solidification defects, as well as strengthening and toughening eutectic composites.