(南昌航空大学 轻合金加工科学与技术国防重点学科实验室，南昌 330063)
摘 要: 采用低功率脉冲激光实现超薄QBe2.5铍青铜与20#钢异种材料的激光点焊，分析工艺参数对QBe2.5/20#钢点焊接头焊缝成形、力学性能和元素含量的影响规律以及显微组织结构。结果表明：随着焊接功率和脉冲宽度的增大，接头焊缝熔深H和熔宽B逐渐增大，且焊缝凹陷越加严重。当焊接脉冲功率为20 W、焊接脉宽为8.0 ms时，其接头抗拉强度可以达到98.36 N。接头主要由富Cu的ε相和富Fe的α相混合组成，而焊缝中Fe元素含量与焊缝总深度L成正相关，Cu元素含量与下凹深度h成反相关。焊接功率和脉宽主要通过改变实际焊缝熔深H和凹陷深度h来改变接头性能。
关键字: 异种材料；激光点焊；显微组织；性能
（National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology, Nanchang Hangkong University, Nanchang 330063, China）
Abstract:The laser spot welding of ultra-thin QBe2.5 beryllium bronze and 20# steel dissimilar materials was realized using low power pulse laser, the influence of parameters on weld formation, mechanical properties and element content of QBe2.5/20 steel spot welding joints as well as its microstructure were analyzed. The results show that, with the increase of welding power and pulse width, the weld depth and width gradually increase, and the weld sag is more serious. When the pulse power is 20 W and the pulse width is 8.0 ms, the tensile shear of the joint can reach 98.36 N. The joint is mainly composed of a mixture of ε phase rich in Cu and α phase rich in Fe, however, the proportion of Fe in the weld is positively correlated with the depth of the weld, while the proportion of Cu is inversely correlated with the depth of the concave. Welding power and pulse width mainly change joint performance by changing weld penetration and sag depth.
Key words: dissimilar materials; laser spot welding; microstructure; joint performance
