航空镍基高温合金的液态热物理性质与组织形成机理研究

Thermophysical properties and microstructural formation of undercooled liquid alloys under simulated space environment are very important for space material and rapid solidification science. As a key material in aircraft engine and gas turbine, Ni-based aerospace superalloys are investigated under simulated space environment by using electromagnetic levitation containerless technique in this project. Through electromagnetic levitation technique, high undercooling and rapid solidification of liquid Ni-based aerospace superalloys are obtained. Meanwhile, the thermophysical properties of liquid Ni-based superalloys are measured by non-contact methods, just like surface tension and specific heat. In addition, the thermophysical properties and heat transfer of liquid metals over a wide temperature range are also calculated by molecular dynamics method. Moreover, the relationships of nonequilibrium solidification characteristics and space environment are studied, just like heat transfer, crystal growth and solute redistribution. Furthermore, the microstructural formation and control methods of liquid undercooled Ni-based superalloys are also explored during solidification process.

空间模拟环境中合金熔体的热物理性质与组织形成机理研究是空间材料科学和快速凝固科学的重要课题之一。本项目以航空发动机和燃气轮机“两机”国家科技重大专项关键材料——航空镍基高温合金为研究对象，利用电磁悬浮无容器处理技术模拟空间环境，实现航空镍基高温合金的深过冷与快速凝固，采用非接触测量方法定量测定稳态与亚稳态镍基高温合金熔体的表面张力、比热等重要热物理性质，结合分子动力学方法计算宽广温度范围内多元镍基高温合金熔体的热物理性质与传热机制，揭示以超高真空、无容器为特征的空间模拟条件与合金熔体快速传热、晶体生长、溶质再分配等非平衡凝固特征之间的耦合规律，进而探索深过冷液态镍基高温合金熔体快速凝固过程中微观组织形成机理与主动调控方法。

空间模拟环境中的高温合金熔体的深过冷与凝固规律对于空间应用科学和快速凝固科学至关重要。本项目聚焦航空发动机和燃气轮机“两机”国家科技重大专项关键材料¬——多元高温合金作为研究对象，利用电磁悬浮无容器处理技术等关键技术模拟空间环境，实现高温合金熔体的深过冷与快速凝固。进而探索空间模拟环境中高温合金熔体的深过冷能力，研究深过冷液态高温合金的热物理性质与快速凝固耦合机制。同时，针对空间模拟环境中合金熔体内部的传热机理开展研究，阐释多种深过冷液态高温合金结晶过程中的传热问题。本项目在部分领域取得突破性进展，可为后续新材料研发奠定坚实基础。