摘要
为了探究螺旋型扫描激光功率对铝合金双脉冲冷金属过渡(cold metal transfer, CMT)增材电弧热场、熔滴过渡行为及气孔缺陷的影响规律,设计变功率激光电弧复合增材制造对比试验,并利用红外热成像、光谱测量和高速摄像技术研究分析引入扫描激光后近熔池表面电弧径向温度场分布、复合交叉区等离子体行为以及对熔滴过渡和气孔缺陷的影响.结果表明,双脉冲CMT近熔池表面电弧径向温度场变化剧烈,温度梯度大,电弧稳定性较低.当引入600~1 200 W扫描激光时,电弧径向温度分布趋于均匀化,温度梯度明显减小,近熔池表面电弧温度显著提高(最高温度可提高约900℃),促使Mg,Al原子电离产生更多数量的Mg Ⅱ,Mg Ⅲ,Al Ⅱ及Al Ⅲ离子,提高电弧稳定性;当激光功率为600 W和1 200 W时,电子密度分别增加6%和17%,电子温度分别提高400 K和800 K.激光金属蒸气有效降低熔滴过渡频率,减弱熔滴对熔池的冲击作用,使熔池趋于稳定;同时,增材件气孔数量明显减少、分布趋于分散化,当激光功率为1 200 W时,气孔几乎消失殆尽.
To study the effect of spiral scanning laser power on the arc thermal field,droplet transfer,and porosity defects in double pulsed cold metal transfer(CMT)additive manufacturing of aluminum alloy,comparative experiments of laser arc additive manufacturing with variable power were conducted.The infrared thermography,spectral measurement,and high-speed imaging technology were used to analyze the radial temperature field distribution of the arc near the molten pool surface,the plasma behavior of the intersection region,the droplet transition,and the porosity defects when the scanning laser was introduced.The results indicate that the radial temperature field of the arc near the molten pool surface exhibits significant fluctuations and a steep temperature gradient with low arc stability in the double pulsed CMT.When the laser power is set to 600–1200 W,the radial temperature distribution of arc becomes more uniform,and the temperature gradient significantly decreases;the arc temperature near the molten pool surface is notably elevated(a maximum increase of 900℃),which promotes the ionization of Mg and Al atoms,resulting in more generation of Mg II,Mg III,Al II,and Al III ions,and improving the arc stability.At laser power of 600 W and 1200 W,the electron density increases by 6%and 17%,and the electron temperature rises by 400 K and 800 K.The laser metal vapor effectively reduces the droplet transfer frequency,lessens the droplet impact on the molten pool,and contributes to greater stability.The number of pores in the components decreases significantly,with their distribution becoming more dispersed;at a laser power of 1200 W,the porosity is almost eliminated.
作者
张刚
刘忠义
蒙旭
石玗
樊丁
ZHANG Gang;LIU Zhongyi;MENG Xu;SHI Yu;FAN Ding(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou,730050,China;Wenzhou Pump and Valve Engineering Research Institute of Lanzhou University of Science and Technology,Wenzhou,325105,China)
出处
《焊接学报》
北大核心
2025年第8期45-54,共10页
Transactions of The China Welding Institution
基金
国家自然科学基金资助项目(52265050)
陇原青年创新创业人才团队资助项目(2022LQTD34)
中科院“西部之光”青年学者人才计划资助项目(21JR7RA202)
兰州市青年科技人才创新资助项目(2023-QN-90)
温州市级科技计划资助项目(2023G0157)。
