强脉冲激光高速冲击焊接基础研究

A novel intense pulse laser high speed impact welding method is developed to meet the requirement of the accurate connection of dissimilar metal materials in micro devices. Based on the theory and experiment, it is established that the high pressure loading model of the flyer plate driven by the laser induced shock wave and the motion process, velocity model and loading characteristics of the flyer plate is revealed under laser irradiation. In addition, a dynamic model of high speed impact between flyer plate and base plate is established. Moreover, the plastic deformation rule, bonding mechanism and interfacial wave formation mechanism of the flyer plate and the base plate under high speed impact are revealed. For further, Microstructure of welding zone and transition zone under laser high speed impact and failure mechanism and control method of welded parts are studied. FEA and SPH methods are combined to reveal function of plastic deformation-time and stress distribution during pulse laser high speed impact process. Morphology characteristics and jet phenomena in the welded interface are simulated and conditions for solid metallurgical bonding are analyzed. The prototype device of laser impact micro welding of metal foil plate is developed. The DOE method is used to design the experiment and study the relationship between micro welding quality and the process parameters of laser impact welding. Basic data of welding window and welding standard of micro welding process is established. Finally, the mechanism and process rule of the micro welding of the metal foil plate driven by the intense pulse laser are revealed. Research results will enrich and develop the theory of high speed impact welding, and lay a solid theoretical foundation for industrial applications of micro parts connection.

针对微器件中异种金属材料精确连接需要，提出强脉冲激光高速冲击焊接新方法。结合理论与实验建立激光诱导冲击波驱动复板的高压加载模型，揭示激光作用下复板的运动过程、速度模型和加载特征；建立复板与基板高速碰撞冲击动力学模型，揭示高速碰撞下复板和基板的塑性变形规律、结合机理及界面波形成机理；研究激光高速冲击焊接区及过渡区的微观结构以及焊接件的失效机理及控制方法；将FEA与SPH方法有机融合，揭示激光高速冲击焊接过程中塑性变形随时间变化的情况与应力分布状况，模拟焊接界面的形貌特征和射流现象，分析固态冶金结合的条件。研发激光冲击金属箔板微焊接原型装置，采用DOE方法进行实验规划和研究微焊接质量与激光冲击焊接工艺参数的关系，建立微焊接工艺可焊性窗口基础数据与焊接规范，最终揭示强脉冲激光驱动金属箔板微连接机理与工艺规律。研究成果将丰富和发展高速冲击焊接理论，并为微器件的微连接工业应用奠定坚实理论基础。

针对微电子、生物医疗器件、精密仪器等领域中微型材料间焊接需求，提出强脉冲激光高速冲击焊接新方法。结合理论、实验与数值模拟系统地研究了激光高速冲击焊接的科学问题。.搭建了激光诱导冲击波冲击压力测试系统，通过复板冲击压力测试结果与经验公式，预测了焊接过程中复板的最大冲击速度；研究了实现有效固态焊接的复板冲击速度和碰撞角度动态范围，揭示激光冲击作用下复板的运动过程、速度模型和加载特征。.搭建了激光高速冲击焊接金属丝/金属箔板、两层金属箔板和三层金属箔板的实验平台，建立了激光高速冲击焊接实验规范化的实验流程；通过不同异种材料组合的激光高速冲击焊接实验，揭示了工艺参数对焊接性能的影响规律，建立了各异种材料组合的激光高速冲击焊接可焊性窗口基础数据与焊接规范。.通过Eulerian方法和SPH方法揭示了激光冲击焊接动态过程在捕捉焊点中心界面特征、界面附近的剪切应力、界面温度分布以及碰撞点处的材料速度分布的能力等冲击动力学特性；揭示了激光高速冲击焊接界面运动学；探明了界面材料的类流体行为，以及射流的形成与喷溅机理。.揭示了高速冲击焊接界面形成的前提条件和界面特征；研究了激光高速冲击焊接金属丝/金属箔板、两层金属箔板和三层金属箔板中的界面波形，探明了工艺参数对界面波形的影响规律；基于SPH模拟和改良后的Jet indentation机理揭示了激光高速冲击焊接界面波形的形成和演变机理；揭示了沿焊接方向界面波形尺寸变化的规律。.通过实验与模拟研究了激光高速冲击焊接中的界面熔化现象；建立了激光高速冲击焊接Al/Ni金属箔板分子动力学模型，揭示了焊接界面的元素扩散现象；研究了激光高速冲击焊接试样中常见的焊接缺陷，揭示了焊接缺陷的产生和扩展机理；探明了激光高速冲击焊接界面的纳米压痕硬度分布、焊接试样最大拉伸力及界面失效形式。.本研究将丰富和发展高速冲击焊接理论，为激光高速冲击焊接材料与工艺参数的选择奠定理论基础，并为异种金属材料固态微焊接的工程应用提供理论和技术支持。