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采用高功率激光束单次冲击3种厚度(1.3 mm,1.7 mm,2.1 mm)的2024铝合金薄板靶材,利用STSS-1应力检测模块采集靶材背面应变片的动态与静态应变信号,并用XRD技术检测了靶材表面残余应力.建立了2024铝合金薄板靶材激光冲击波加载模型,并利用该模型描述了靶材内部应力波结构及传播规律,解释了冲击区域残余拉应力产生的原因.结果表明,激光冲击2024铝合金薄板靶材时,激光诱导的冲击波和约束层对冲击波的反射波透射到靶材内部各部位的应力波具有不同的特性和强度变化规律.激光功率密度远超出2024铝合金最佳激光功率密度范围和靶材厚度较薄这2个条件同时存在是冲击区域残余拉应力产生的根源所在.
A high-power laser beam was used to impact 2024 aluminum alloy thin plate targets of three thicknesses (1.3 mm, 1.7 mm, 2.1 mm). The STSS-1 stress detection module was used to acquire dynamic and static strain signals of the back surface of the target. XRD technique was used to detect the residual stress on the target surface.The laser shock wave loading model of 2024 aluminum alloy thin plate target was set up and the stress wave structure and propagation law of the target was described by this model and the reason of the residual tensile stress in the impact region was explained. The results show that the laser-induced shock wave and the constraint layer have different characteristics and intensity variation on the stress waves transmitted to the internal parts of the target by the laser-induced shock wave and constraint layer when the laser beam impacts the 2024 aluminum alloy thin plate target. The coincidence of the best laser power density range of aluminum alloy and the thin target thickness is the root cause of the residual tensile stress in the impact region.