重型燃气轮机定向结晶叶片的材料与制造工艺-中国材料进展

文章信息/Info

Title:: Material and Processing Technology of Directionally Solidified Blade in Heavy Duty Industrial Gas Turbines

Author(s):: ZHANG Jian; LOU Langhong; LI Hui; (Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China)

摘要:: 重型燃气轮机是我国能源发展战略中的关键装备。在高温和热腐蚀环境下工作的透平叶片，是重型燃机的核心热端部件。与航空发动机叶片比较，先进重型燃气轮机透平叶片，在高温热腐蚀环境下长期工作，而且叶片的尺寸较大，因此，对叶片使用的高温合金材料及其制造工艺均提出了特殊的要求。用于燃气轮机叶片的抗热腐蚀高温合金材料，经历了从多晶到定向和单晶的发展历程，其合金在设计中具有高Cr，高Ti，Al比等几个显著区别于航空发动机叶片材料的特征。兼顾高强度、优异抗热腐蚀性能及长期组织和性能稳定性的燃气轮机用铸造高温合金的研发，因此更具挑战。定向凝固是重型燃气轮机用大型定向结晶叶片制造工艺中最为关键的技术之一。介绍了先进定向凝固技术——高温度梯度液态金属冷却定向凝固技术的发展，对比了不同定向凝固工艺对高温合金典型组织及力学性能的影响，并简单介绍了我国近期在大型定向结晶叶片研制方面的进展。

Abstract:: Turbine blades used in heavy duty industrial gas turbines (IGT) serve at high temperatures and in an aggressive environment. The present paper gives an overview of the materials and processing techniques of IGT blades. Comparing to the turbine blades used in aero engines, IGT blades operate at high temperature, hot corrosion environment for longer time, and are with much larger size. The principles of material design and manufacture of these large blades are therefore required with special considerations. The temperature capability of materials used as IGT blade is increasing over the past decades due to the development of directionally solidified (DS) and single crystal superalloys. Features such as high Cr content and Ti/Al ratio are unique in these alloys comparing to the alloys used in aero engines. Consequently, development of alloys with high strength, high hot corrosion resistance, as well as good long term stabilities is a very challenged task. Directional solidification is one of the most important techniques in manufacturing the large blade. The development of advanced high gradient DS processliquid metal cooling process has been described. Typical microstructure and properties of superalloys processed by different DS techniques are compared. Some recent progresses in manufacturing the large blades in China have also been depicted.