超声波作用下金属熔滴碰撞固体表面的润湿铺展行为及调控机制

金属增材制造、热喷涂和电子封装等工艺都与单体液滴在基板表面的铺展润湿行为有密切关系，在这些工艺中施加超声波，能减小飞溅、提高致密度、减少气孔等缺陷，为获得性能优良的产品提供良好的条件。但由于国内研究基础薄弱，严重制约了超声波在金属增材制造和热喷涂中的应用。以增材制造、热喷涂、电子封装常用的金属液滴和基板作为研究对象，引入超声波作为外加物理场，通过物理场参量的变化，考察由此引起的铺展润湿行为及液滴凝固并与基板界面反应的变化，旨在揭示超声波作用于金属喷射沉积体系润湿铺展和凝固组织的内在调控机理，建立起超声波作用下润湿铺展的热/动力学、凝固组织显微结构与超声波的联系，明晰它们的相互作用，完善并提出以熔滴碰撞基板为基础的外场作用机制，提出金属增材制造和热喷涂过程中控制沉积层质量的理论基础及优化工艺的方法。研究解决复合场增材制造技术中的重大基础问题，为提升我国先进材料制备及加工技术提供科学依据。

These process such as metal additive manufacturing, thermal spraying and electronic packaging are closely related to the wetting behavior of droplets on the substrate surface. By applying ultrasonic to these process can reduce splatter, increase density, reduce porosity and other defects, a good manufacturing environment can be formed, which results in the performance of products can be improved. But due to the basic research is poor in our country, which results in ultrasonic application on process of metal additive manufacturing, thermal spraying and electronic packaging is restricted seriously. In this project some typical metal droplets and substrate systems to be applied to metal additive manufacturing, thermal spraying and electronic packaging were selected. The ultrasonic fields were also added as the extra physic fields. The wetting and spreading behavior, solidification structure and interfacial strducture evolution were studied. The main purposes of this study are to reveal the controlled mechanism of wetting and spreading and solidification structure under sound field, and then to connect the relation of wetting and spreading behavior, solidification structures and parameters of sound field. Base on above, the basic theories of wetting and spreading control for metal droplets and substrate systems would be replenished and a new way for the optimization in the process would also be proposed. This is a key research for basic theoretical questions of manufacturing and processing under physics field , to provide the scientific basis for improving and upgrading the processing techniques of manufacturing and processing of advanced materials.