为了研究激光－电弧复合焊接的热源相互作用，提升对复合焊接复杂物理过程的认识程度，进一步优化工艺参数，采用CO₂轴快流激光器和钨极氩弧焊机在3mm厚316L不锈钢板上进行了复合焊接试验研究。定义无量纲参数——复合焊接熔化效率增量δ来表征热源相互作用的变化。结合焊缝成形、等离子体形貌，通过δ半定量分析了激光、电弧热源间距和能量配比对热源相互作用的影响。结果表明，在优化的参数组合下，δ高达83．6%。其中，电弧对工件的预热作用能够提高激光能量的利用率，增强热源相互作用，但是激光－电弧等离子体相互作用才是提高热源相互作用程度的关键机制。

The investigation on the interaction of laser induced plasma and arc plasma in the laser-arc hybrid welding process benefits the understanding of complicate physical phenomenon and the optimization of welding parameters. So far,the research materials about this are few. A detail experiment of laser-arc hybrid welding was carried out on 3mm thickness 316L stainless steel by a 5 kW CO₂,laser together with a TIG(tungsten inert gas)welder. A dimensionless parameter,the increment of melting efficiency of hybrid welding δ,is defined to indicate the heat sources interaction of laser and arc. With the bead shape,plasma shape and δ,the effect of heat sources distance and energy ratio of laser and arc was semi-quantitative analyzed. The results show that with the optimized combination of welding parameters,δ can reach 83.6%. Moreover,the preheating of arc on the work-piece can improve the efficiency of laser power and enhance the heat sources interaction,but the laser-arc interaction is the key mechanism to improve the heat sources interaction.