摘要
新型冷金属过渡与脉冲(CMT+P)复合电弧技术实现了对电弧能量的精细控制,为获得高质量电弧增材成形件提供了可靠保证;然而CMT与脉冲协同作用过程中的熔滴过渡行为尚不清晰,其对增材过程稳定性、成形质量有重要影响。以高强铝合金为研究对象,基于流体力学和电磁学理论,采用动网格与界面追踪技术,综合运用数值模拟和原位观测试验手段研究了高强铝合金CMT+P电弧增材过程中的熔滴过渡行为。结果表明模拟结果与试验结果高度吻合;平均送丝速度为5 m/s时高强铝合金CMT+P电弧增材工艺的熔滴过渡呈现CMT阶段的短路过渡和脉冲阶段的一脉一滴射滴过渡的混合过渡模式;在短路阶段由熔丝机械拉力形成的金属液桥可有效避免熔滴飞溅,提高成形质量;在脉冲阶段熔滴受电磁力、表面张力、Marangoni力、重力和等离子流力耦合作用,在内部形成静止区,速度在静止区收敛或发散,呈流速上下反向的特点,进而影响熔滴过渡的稳定性。
The new technology of Cold Metal Transfer and Pulse(CMT+P)composite arc realizes the fine control of arc energy,and provides a reliable guarantee for obtaining high-quality arc additive formed parts.However,the drop⁃let transfer behavior in the synergistic action of CMT and pulse is not clear,which impacts heavily on the stability of ad⁃ditive process and forming quality.Based on the theory of hydrodynamics and electromagnetism,this paper takes high-strength aluminum alloy as the research object,adopts dynamic grid technology and interface tracking technol⁃ogy,and comprehensively uses numerical simulation and in-situ observation test methods to clarify the evolution mechanism of droplet transfer behavior in the process of CMT+P arc additive of high-strength aluminum alloy.The re⁃sults show that the simulation results are highly consistent with the experimental results.When the average wire feed⁃ing speed is 5 m/s,the droplet transfer of high-strength aluminum alloy CMT+P arc additive process presents a mixed transition mode of short-circuit transition in CMT stage and one pulse one drop ejection transition in pulse stage.The metal liquid bridge formed by the mechanical tension of the fuse in the short circuit stage can effectively avoid the splashing of molten droplets and improve the forming quality.In the pulse stage,the droplet is coupled by electromag⁃netic force,surface tension,Marangoni force,gravity and plasma flow force to form a static area.The velocity con⁃verges or diverges in the static area,forming the characteristics of upward and downward reverse flow velocity,which further affects the stability of droplet transition.
作者
张志强
勾青泽
路学成
王浩
曹轶然
郭志永
ZHANG Zhiqiang;GOU Qingze;LU Xuecheng;WANG Hao;CAO Yiran;GUO Zhiyong(College of Aeronautical Engineering,Civil Aviation University of China,Tianjin 300300,China;Mechanical Science and Engineering College,Tianjin University of Technology and Education,Tianjin 300222,China)
出处
《航空学报》
EI
CAS
CSCD
北大核心
2023年第13期250-261,共12页
Acta Aeronautica et Astronautica Sinica
基金
天津市教委教研计划(2020KJ020)
航空科学基金(2020Z049067002)。
关键词
冷金属过渡加脉冲
电弧增材制造
熔滴过渡
流场
高强铝合金
cold metal transfer plus pulse
arc additive manufacturing
droplet transfer
flow field
high strength aluminum alloy
作者简介
通信作者:王浩.E-mail:wanghao022tj@163.com。
