弹性预加载下板料激光喷丸成形特性

分析了弹性预加载下激光喷丸成形的机制,并通过试验研究了板料在弹性预加载下激光喷丸成形的特性。试验用的激光脉冲参数为:波长1.06μm,脉宽23 ns,光斑直径4 mm,功率密度109W/cm2量级;试样的材料为LY12CZ硬铝合金。试验结果表明,在弹性预加载下,板料在弹性预弯方向获得的弯矩要比与弹性预弯垂直方向上的弯矩大得多,弹性预加载下激光喷丸成形可以有效地克服自由状态下激光喷丸件呈球形现象,激光喷丸件的曲率是自由状态下激光喷丸成形曲率的2~3倍;在相同曲率下,弹性预加载下激光喷丸成形件的表面粗糙度比自由状态下激光喷丸成形件的表面粗糙度要低1~2等级,因此弹性预加载下激光喷丸成形要优于自由状态下的激光喷丸成形。

Characteristics of Deformation of Plate by Laser Peening under the Elastic Pre-Loading Condition

Laser peening forming is a novel technology, which employes the residual stress induced by high-power repetition laser to form plate. The mechanism of laser peening forming under elastic pre-loading condition was analyzed and the feature of deformation was tested by experiments. In the experiments, the parameters of laser were as follows: the wavelength is 1.054 μm, the pulse duration is 23 ns, and the power dsnsity is 109 W/cm2. The material of sample was LY12CZ aeronautic aluminum alloy. The experimetal results show that the flexural moment of the sample in the prebending direction is far bigger than that in the vertical direction to pre-bending and the spherical shape can be conquered during pre-loading laser peening forming to a great extent. Under the same conditions, curvature of workpiece after the pre-loading laser peening is two to three times than that after laser peening without pre-loading, and the surface roughness can be improved by one to two grade. So the laser peening forming during pre-loading is superior to the laser peening without pre-loading.