钢/铌电子束焊接接头金属间化合物生长机制及调控研究

The welded structure of steel/niobium has broad application prospect in the aerospace industry, but the welded joint of steel/niobium can easily generate intermetallic compound(IMC) which will significantly reduce the performance of joint, so this project intends to study the growth mechanism and regulation measures of IMC. The types、amounts、shapes and distributions of IMC of joint are analyzed so as to provide direct experimental data for the following simulation study. The phase field method is used to simulate the evolution and growth kinetics behavior of IMC of joint, which will lay the foundation for clarifying the growth mechanism of IMC. The evolutionary process of IMC is simulated by the thermal physical simulation method so that the numerical simulation results are verified and supplemented. Combining simulation and experimental results, the IMC growth mechanism will be clarified, and the influence law of interfacial energy、diffusion coefficient of grain boundary and other factors to the IMC growth will be revealed. The method of energy-metallurgy combined regulation is used to control the IMC of joint. The influence mechanism of energy-metallurgy combined regulation to evolution and growth kinetics behavior of IMC will be clarified based on the influence law of interfacial energy、diffusion coefficient of grain boundary and other factors to the IMC growth, the mathematical model between parameters of welding procedure and the thickness of interfacial IMC layer is established, and the mathematical model between the thickness of interfacial IMC layer and the tensile strength of joint is also established, so the quantitative relationship between welding procedure and joint microstructure，as well as between joint microstructure and joint properties will be revealed, the theoretical guidance for the active regulation of IMC of welded joint of dissimilar metal will be provided by the above study.

钢/铌焊接结构在航空航天工业具有广阔的应用前景，但是钢/铌焊接接头极易生成金属间化合物（IMC），显著降低接头性能，因此本项目拟研究IMC生长机制及其调控措施。分析IMC的种类、数量、形态和分布，为后续的模拟研究提供直接的试验数据。采用相场法对IMC演化和生长动力学行为进行数值模拟，为阐明IMC生长机制打下基础。基于热物理模拟法模拟IMC演化过程，对数值模拟结果进行验证和补充。结合模拟和试验结果，阐明IMC生长机制，揭示界面能、晶界扩散系数等因素对IMC生长的影响规律。采用能量-冶金联合调控法对IMC进行调控。以界面能、晶界扩散系数等因素对IMC生长的影响规律为桥梁，阐明能量-冶金联合调控对IMC演化和生长动力学行为的影响机制，建立焊接工艺参数、界面IMC层厚度和接头抗拉强度之间的数学模型，揭示焊接工艺、接头显微组织和接头性能之间的定量关系，为异种金属焊接接头IMC主动调控提供理论指导。

钢-铌焊接结构在航空航天工业具有广阔的应用前景，但是钢-铌焊接接头极易生成金属间化合物（IMC），显著降低接头性能，本项目对钢-铌激光焊接接头的IMC生长机制及其调控措施进行了试验研究和理论分析。分析了IMC的种类、数量、形态和分布。揭示了接头IMC的演化和生长动力学行为，阐明了IMC生长机制，采用能量-冶金联合调控法对IMC进行调控。揭示了能量-冶金联合调控对接头显微组织和残余应力的影响机制，阐明了焊接工艺↔接头显微组织/残余应力↔接头力学性能之间的内在联系。预期研究成果有望为异种金属焊接接头力学性能的改善开辟新的途径，为钢-铌焊接结构在航空发动机中的应用提供技术支撑。