采用脉冲激光点焊的方法, 对厚度为1.5 mm的锆基非晶合金实现了有效连接, 并研究了激光峰值功率、脉宽和离焦量及三者之间的交互作用对焊点表面直径、熔深和单个焊点承受最大载荷的影响, 基于响应面优化方法对焊接工艺参数进行优化, 建立焊点表面直径、熔深和单个焊点承受的最大载荷与激光峰值功率、脉宽和离焦量之间的数学模型, 对数值模型进行了验证。脉冲激光点焊厚度为1.5 mm的锆基非晶合的优化出工艺参数为峰值功率1.2～1.21 kW, 脉宽5.96～6.0 ms, 离焦量-1.78～-2.00 mm。在此焊接参数范围内, 焊点表面直径为0.892～0.895 mm, 熔深为2.479～2.514 mm, 单个焊点能承受的最大载荷为109.2～110.3 N。研究结果表明, 随焊接峰值功率和脉宽的增大, 焊点表面尺寸和熔深增加, 热影响区的晶粒尺寸增大。当热影响区出现纳米晶粒时, 单个焊点能承受的最大载荷呈增大趋势, 当晶粒长大至4 μm后, 单个焊点能承受的最大载荷呈减小趋势, 其原因为大晶粒的出现导致大量位错聚集, 成为微观裂纹源。离焦量主要影响熔深, 随着离焦量由-2.0 mm变化至-0.4 mm, 熔深逐渐减小, 而单个焊点能承受的最大载荷和表面尺寸变化较小。

The pulsed laser spot welding method was used to realize the effective connection of Zr-based amorphous alloy with thickness of 1.5 mm. The effects of laser peak power, pulse width and defocus amount and the interaction between the three on the surface diameter, penetration depth and single point maximum load were studied . Based on the response surface optimization method, the welding process parameters were optimized, and the mathematical model between the surface diameter, penetration depth, the single point maximum load and the laser peak power, pulse width and defocus amount was established. The numerical model was verification. The optimum process parameters of pulsed laser spot welding thickness of 1.5 mm Zr-based amorphous alloy are as follows: the peak power is 1.2～1.21 kW, the pulse width is 5.96～6.0 ms, the defocus amount is -1.78～-1.20 mm. Within the range of welding parameters, the surface diameter of the solder joint is 0.892～0.895 mm, the penetration depth is 2.479～2.514 mm and the maximum load of a single solder joint is 109.2～110.3 N. The results show that with the increase of peak power and pulse width, the surface diameter and penetration depth of solder joint increase, and the grain size of the heat-affected zone increases. When the nanocrystalline grains appear in the heat-affected zone, the maximum load of a single joint can bear increases. When the grain grows to 4 μm, the maximum load of a single joint can bear decreases, mainly due to the appearance of large grains leads to the accumulation of a large number of dislocations and becomes the source of microcracks. The amount of defocus mainly affects the penetration depth, and as the defocus amount changes from -2.0 mm to -0.4 mm, the penetration depth gradually decreases, while the maximum load and surface dimension change that a single joint can withstand are small.