电磁/超声耦合作用下激光熔覆金属陶瓷涂层的形性协同调控机制

To solve the challenge of internal stress and metallurgical defects generated by laser cladding during process of preparing metal-based ceramic coating , a new method for high-performance coating prepared by laser cladding assisted with electromagnetic / ultrasonic technique is investigated, and the research on the regulation of compound energy fields and microstructure / stress is developed. Three following issues will be focused in this proposal. The first is to study the space-time modulation and coupling equations of the electromagnetic / ultrasonic compound energy field, explore the influence of acoustic and magnetic coupling on thermodynamics of molten pool, reveal the micro-motion mechanism of reinforced particles under the multi-energy fields in molten pool. The second is to study the solidification process of laser cladding under the compound energy fields and the mechanism of uniform grain refinement, explore the distribution of ceramic reinforced particles and the evolution law of microstructure, reveal the residual stress and defect elimination mechanism of the cladding controlled by the electromagnetic / ultrasonic technique. The third is to develop the strong correlations between the process parameters, microstructure and performance, reveal the coordinated mechanism of stress and structure on the shape / performance of the cladding layers, explore the method of intelligent multi-parameter coordination under the external energy fields. The above research involves many new scientific issues, and these research achievements can not only enrich and develop the basic theory of compound energy fields processing, but also provide technical support for the engineering application of high-performance coating prepared by laser cladding.

针对金属陶瓷涂层激光熔覆制备中内应力诱导的变形开裂和冶金缺陷造成的性能不佳等问题，本项目探索电磁/超声耦合作用下激光熔覆制备高性能涂层的新方法，开展复合能场协同调控熔覆涂层组织/应力的机制研究。主要包括：（1）研究激光熔覆过程中电磁/超声复合能场的时空调制及其耦合方程，探索声磁耦合作用对熔池热动力学影响规律，明晰多场作用下熔池增强颗粒的微观运动机制；（2）研究复合能场作用下激光熔覆凝固相变过程及其晶粒均匀细化机理，分析陶瓷增强颗粒分布及其微观组织演变规律，阐明电磁/超声复合能场调控熔覆层残余应力及其缺陷消除机制；（3）研究工艺参数–微观组织–涂层性能之间的内在关联，明晰应力和组织对熔覆层的形/性协同影响机制，探索电磁/超声能场作用下多参数关联的优化调控方法。相关内容涉及诸多全新科学问题，研究成果有望丰富和发展多能场复合制造的基础理论，为激光熔覆制备高性能涂层的工程应用提供技术支撑。

针对金属陶瓷涂层激光熔覆制备中出现的变形开裂、冶金缺陷及组织不均等问题，本项目提出了电磁/超声辅助激光熔覆制备涂层新方法，开展了电磁/超声复合能场作用下熔池传热传质、凝固过程、组织演变及其性能调控相关研究。主要进展和成果如下：（1）研究了电磁/超声能场作用下激光熔覆熔池内的热质传输特性，建立了超声诱导熔池的非线性效应与电磁诱导的洛伦兹力的理论关系模型，分析了电磁、超声能场作用下熔池内温度场和流场的分布特性，揭示了电磁/超声复合能场在熔池中的协同作用机制；（2）基于相场法研究了电磁/超声条件下激光熔覆熔池的凝固过程，分析了能场调控熔池内部WC颗粒的空间分布特征，得到了复合能场对熔池温度梯度的影响规律，明晰了电磁超声能场对涂层WC陶瓷颗粒分布及其组织演化的调控机制；（3）研究了外加能场对复合涂层表面/截面形貌及内部缺陷的影响，探讨了激光熔覆陶瓷复合涂层内部气孔与应力形成过程，揭示了电磁/超声能场对熔覆组织内部气孔和裂纹调控机制及其涂层性能增强机理；（4）研究了电磁/超声复合激光熔覆涂层表面磨损形貌与不同能场下的磨损机制，获得了能场改善涂层组织、冶金缺陷以及陶瓷增强颗粒的分布规律，明晰了应力和组织晶粒对涂层形/性协同控制的影响，揭示了电磁/超声能场下涂层磨损性能的增强机理；（5）提出了基于支持向量机能场辅助激光熔覆工艺参数优化方法，建立了融合粒子群算法与支持向量机的PSO-SVR预测模型，实现了优化工艺参数下熔覆层几何特征和显微硬度的预测，为电磁/超声复合能场辅助激光增材工艺方的工程应用提供了基础。围绕项目研究，发表相关学术论文15篇，其中SCI收录13篇，EI收录2篇，TOP期刊5篇；授权发明专利7件，含PCT美国/英国专利2件；相关成果获2021年度江苏省科学技术奖二等奖1项，培养青年教师2名，博士生2名，硕士生9名。