Nanosecond pulsed laser welding of 316L stainless steel and 6063 aluminum alloy thin sheets was performed. The influence of scan line spacing on the joining process was clarified. Large explosive hole and hot cracking defects including radial cracks and arc-shaped cracks occurred in the joint caused by excessive heat accumulation when the line spacing was 0.02 mm. The joints without oxidation were obtained. The thermal-induced penetration increment (TIPI) decreased with the increase of line spacing and reached the maximum value of about 162.24% with the line spacing of 0.02 mm. Fe₂Al₅ and FeAl phases probably were produced at all the line spacings. However, FeAl and α-Fe phases in the form of banding structures were possibly generated only with the line spacing of no less than 0.06 mm. The shear force test results indicated that the maximum shear load of 158.8 N was achieved at the line spacing of 0.06 mm due to the large bonding area and fewer defects. Three fracture paths, namely, button pullout failure (BPF), interfacial failure (IF) and mixed fracture (MF) mode of BPF and IF were produced. The heat affected zone was the origin of BPF mode. Local deformation, pores and Fe-Al brittle phases led to the fracture paths of IF and MF.

进行了316L不锈钢和6063铝合金薄板的纳秒脉冲激光焊接。阐明了扫描线间距对接合工艺的影响。当线距为0.02 mm时，由于热量过度积累，接头处出现大的爆孔和热裂纹缺陷，包括径向裂纹和弧形裂纹。获得没有氧化的接头。热致穿透增量（TIPI）随着线距的增加而减小，线距为0.02 mm时达到最大值约162.24%。Fe ₂ Al ₅和 FeAl 相可能在所有线间距处产生。然而，带状结构形式的 FeAl 和 α-Fe 相可能仅以不小于 0.06 mm 的线间距产生。剪切力试验结果表明，由于结合面积大，缺陷少，线间距为0.06 mm时达到了158.8 N的最大剪切载荷。产生了三种断裂路径，即按钮拔出失效（BPF）、界面失效（IF）和 BPF 和 IF 的混合断裂（MF）模式。热影响区是 BPF 模式的起源。局部变形、孔隙和 Fe-Al 脆性相导致 IF 和 MF 的断裂路径。