针对T2紫铜箔材开展了多脉冲激光冲击微胀形实验,研究了激光功率密度、初始晶粒尺寸和箔材厚度对胀形极限的影响,分析了断裂工件的宏观和微观断口形貌,讨论了箔材在多脉冲激光冲击微胀形时的断裂模式,并分析了各断裂模式的产生机理。研究结果表明:激光功率密度会显著影响箔材断裂前可承受的最大脉冲次数,但多脉冲成形方式不能提高箔材的胀形成形极限;晶粒尺寸和特征尺寸对多脉冲激光冲击微胀形成形极限具有显著影响;紫铜箔材在多脉冲激光冲击微胀形时存在拉伸断裂、剪切断裂、混合断裂和层裂4种断裂模式。

Multiple-pulse laser shock micro-bulging experiments of T2 pure copper foils are conducted. The effects of laser power density, initial grain size and foil thickness on forming limit are investigated. Macro and micro fracture morphology of broken work are analyzed. The fracture mode of copper foils in multiple-pulse laser shock micro-bulging is discussed, and the mechanisms of four fracture modes are analyzed. Research results show that the laser power density has a significant influence on the maximum pulse number before fracture occurrence. In addition, the forming limit of foil cannot be increased through multiple-pulse forming method. Both grain size and feature size have a significant impact on the forming limit of multiple-pulsed laser shock micro-bulging. There are four fracture modes in multiple-pulse laser shock micro-bulging, that is, tensile fracture, shear fracture, mixed fracture and spallation.