液态金属冷却法制备镍基单晶高温合金铸件的研究进展  

Research Progress of Ni-based Single Crystal Superalloy Castings Prepared by Liquid Metal Cooling Technique

作　　者：艾诚 张龙 郭敏[2] 黄太文[2] 刘林[2] AI Cheng;ZHANG Long;GUO Min;HUANG Taiwen;LIU Lin(School of Materials Science and Engineering,Chang’an University,Xi’an 710064;State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072)

机构地区：[1]长安大学材料科学与工程学院,西安710064 [2]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《机械工程学报》2024年第24期127-141,共15页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51701020,5197174,52071267);中央高校基本科研专项资金(300102313101,300102312407)资助项目。

摘　　要：与目前已在工业上得到广泛应用的快速凝固法(High rate solidification,HRS)相比,液态金属冷却法(Liquid metal cooling,LMC)具有更高的温度梯度,因此在制备大尺寸单晶涡轮叶片时具有显著的优势。归纳总结HRS与LMC技术的工作原理与温度梯度,由HRS与LMC技术制备的单晶高温合金铸件的枝晶组织、显微偏析、固溶处理、显微孔洞、铸造缺陷形成倾向与力学性能等特点。与HRS技术相比,LMC技术可显著地细化枝晶间距,并降低铸态组织中元素的显微偏析倾向;LMC技术可有效地降低固溶处理难度,并降低铸态和热处理态合金中显微孔洞的数量和尺寸;LMC技术可有效地降低定向凝固时雀斑和缘板杂晶等铸态缺陷的形成倾向;在较低的服役温度下,LMC技术可有效地提高合金的低周疲劳性能和高周疲劳性能。然而,LMC技术存在选晶器中引晶段晶体取向控制效果较差和Sn污染等问题,需要采用优化定向凝固工艺参数和使用高强度定向凝固型壳等方法解决上述问题。At present,high rate solidification(HRS)technique had been widely used in industry.As compared with HRS technology,liquid metal cooling(LMC)technology had higher temperature gradient,and thus it had an advantage in the preparation of single crystal turbine blades with large size.This paper summarized the working principle and temperature gradient of HRS and LMC technologies,as-cast microstructure,solution treatment,formation tendency of casting defect and mechanical properties of single crystal superalloys(prepared via HRS and LMC technologies).As compared with HRS technology,LMC technology can significantly refine dendrite arm spacing and reduce the microsegregation tendency of alloying elements in as-cast microstructure.LMC technology can effectively reduce the difficulty of solution treatment and decrease number and size of micro-pores in both as-cast and heat-treated single crystal superalloys.Meanwhile,LMC technology can effectively reduce the formation tendency of as-cast defects(e.g.freckles and stray grain at platform region).At relatively low service temperature,LMC technology can effectively improve the low cycle and high cycle fatigue properties of single crystal superalloys.However,LMC technology might led to relatively poor crystal orientation control effect during grain selection and Sn contamination,and the above problems needed to be solved by optimizing directional solidification process parameters and shell preparation process.

关 键 词：液态金属冷却法 镍基单晶高温合金 显微组织 固溶处理 铸造缺陷 力学性能 

分 类 号：TG156[金属学及工艺—热处理]