金属板材的激光冲击成形通常采用激光束沿法向作用于零件表面,产生垂直于表面的冲击波作用力,但在曲面零件冲击成形时很难满足每次都为法向垂直冲击,因此非常有必要进行斜冲击研究。用钕玻璃激光器斜冲击LD31(6063)板料,并使用千分尺对变形特征进行了测量,实验表明等离子体的迎光性以及等离子体与激光之间的相互作用使得等离子体逆着激光方向斜膨胀,产生的应力波则顺着激光方向斜冲击板料,造成了被冲击板料变形的偏心。在激光能量约为42 J,脉冲宽度约为23 ns,光斑直径为8 mm,入射角度约为0°,30°,60°时,板料的偏心依次为1.00 mm,1.68 mm,3.77 mm,深度方向变形依次为5.60 mm,5.00 mm,3.00 mm,变形最大点显微硬度提高率依次为50%,33.3%,25%。

The formation of the metal sheet by the laser shock usually utilizes the laser shock wave that is vertical to the surface of the sheet. But it is difficult to make that the laser is vertical to the surface of the metal sheet when processing the blending surface. So it is necessary to clarify the principle of the oblique angle laser shock. The LD 31 Al is obliquely shocked by the laser, the data of the deformation are measured by the micrometer. The results show that the plasma produced by laser shock expands obliquely against the direction of the laser beam. The characteristics of moving back-ward the laser as well as the principle of the interaction between the laser beam and plasma are researched. The stress wave of the expanding plasma goes along the direction of the laser beam then the sheet is shocked obliquely by the stress wave. The distance between the center of the deformation of the sheet and the geometric center is in order of 1.00 mm, 1.68 mm, 3.77 mm, when the incidence angle is in order of ～0°, 30°, 60° under the laser energy of 42 J, pulse duration of 23 ns and beam diameter of 8 mm. The deformation in depth is in order of 5.60 mm, 5.00 mm, 3.00 mm, and the elevation of the microhardness on the surface of the biggest deformation point is in order of 50%, 33.3%, 25%, when the incidence angle is one by one in order of ～0°, 30°, 60°.