脉冲激光间接加载金属薄板动态精微塑性成形基础研究

According to the demand of manufacturing metal micro-part with high efficiency and precision, this project utilizes flexible rubber material as a soft punch, under the pressure generated by laser-induced shock wave, to act on the thin metal sheet.The forming and punching can be performed at the same time in one operation with forming/punching die. The mechanism of indirect dynamic loading using laser shock rubber is investigated, and the effect of the rubber on forming capability、quality and accuracy is also studied.The dynamic plastic deformation mechanism of the thin metal sheet is investigated, and the micro-structure evolution, grain refinement and strengthening micro-mechanisms are also studied.The effect of dynamic loading on size effect and the associated dynamic plastic flow behavior、fracture behavior、elastic recovery、frictional behavior and surface roughening are investigated.Coupling Influence of forming temperature、strain rate and size effect on plastic micro-formability is explored.The relations of the quality and accuracy of micro-part and process parameters are investigated to establish the basic data and technological criterion of micro-forming.Rubber is introduced as a soft punch to smooth laser shock wave pressure, so the forming capability、quality and accuracy can be improved,The dynamic plastic deformation can result in the grain refinement and ultra-refinement of sample,so it can overcome the size effect to some extent. This project involves many scientific problems, research results will play an important role on the development of the plastic deformation and fracture theory of the thin metal sheet under dynamic loading.

面向高效高精度地制造微零件的需求，提出一种利用激光冲击波作用聚合物软膜间接加载金属薄板，结合成形/冲裁微模具在单脉冲激光作用下同时实现微成形和微冲裁，从而直接制造金属微零件的新方法。研究激光冲击软膜间接动态加载机制及其对微成形能力、质量和精度的影响；研究金属薄板动态塑性变形及微观组织演化、晶粒细化与微观强化机制；揭示动态加载对尺寸效应相关的塑性流动行为、断裂行为、回弹、摩擦行为等的影响规律；探讨成形温度、应变率、尺寸效应对微成形能力的耦合影响，研究成形与冲裁件质量、精度与工艺参数间的关系，建立微塑性成形的基础数据与工艺准则。聚合物软膜作为柔性冲头可有效均化激光冲击波压力分布，提高工件的成形能力、精度和质量，动态塑性变形使工件的内部组织细化甚至超细化，从而在一定程度上克服微成形中尺寸效应的影响。相关研究将涉及众多科学问题，研究成果将丰富和发展动态加载下金属薄板的塑性形变与断裂理论。

本项目面向高效高精密制造微零件的需要，提出一种利用激光冲击波作用聚合物软膜间接加载金属薄板，结合成形/冲裁微模具在单脉冲激光作用下直接制造金属微零件的新方法。.研究了激光冲击聚合物软膜的加载特性及软膜的动力学响应特性，揭示聚合物软膜对激光冲击波压力空间分布的均化效应及增压机制，探明了软膜不同材料特性及几何尺寸对激光柔性冲击微成形工件成形精度的影响规律，为实现高精密微零件的制造奠定理论基础。.研究了微冲裁、微胀形、微弯曲等多种类型的激光间接加载金属薄板动态精微塑性成形工艺。实验揭示了激光参数、软膜特征参数、薄板参数、模具形状及特征参数、成形温度对成形性能的影响规律。借助有限元仿真软件对激光柔性冲击微成形的变形历程进行深入探索，表征工件内部的等效塑性应力及应变分布，揭示了微成形过程中工件的动态响应及塑性变形规律。.基于相似性原理设计微模具和工件参数，研究晶粒尺寸和特征尺寸对微胀形件表面粗化行为、塑性流动行为、断裂行为、回弹行为的影响，揭示了高应变率微成形中的尺寸效应现象，探究了激光冲击、温热对尺寸效应的改善作用，为精微塑性成形提供理论指导。.研究多类金属微冲裁件的断面形貌及断裂模式，揭示了激光柔性冲击微冲裁机理。研究动态加载下材料的动态再结晶现象及其在热力耦合加载下的失效形式。对微成形件进行力学性能表征，探究了绝热温升软化效应及高速冲击硬化效应的相互竞争机制。 .对激光柔性冲击薄板后的显微特征进行表征，研究成形件在不同形变模式和形变阶段的微观组织演变规律。探明了成形过程中的亚晶粒、纳米晶、二次孪晶等晶粒细化机理。基于分子动力学模拟研究了纳米多晶铜及纳米孪晶铜在高应变率加载下微观组织演化过程，演绎了位错运动、纳米孪晶束、二次孪晶、孪晶相交等现象，从原子层面揭示了纳米结构的形成机理和对材料性能的提升。 .研究成果将丰富和发展动态加载下金属薄板的塑性成形知识，并为工程应用提供理论和技术支持。