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Study on droplet transfer behavior of high strength aluminum alloy cmt+p arc additive manufacturing

  

  • Received:2022-08-01 Revised:2022-09-09 Online:2022-09-22 Published:2022-09-22
  • Supported by:
    National Natural Science Foundation of China;Aeronautical Science Foundation of China;Scientific Research Project of Tianjin Education Commission;Science and Technology program of Tianjin

Abstract: The new technology of cold metal transition 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 droplet transfer behavior in the synergistic action of CMT and pulse is not clear, which has an important impact on the stability of additive 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 technology, 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 results show that the simulation results are highly consistent with the experimental results. When the average wire feeding 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 electromagnetic force, surface tension, Marangoni force, gravity and plasma flow force to form a static area. The velocity converges or diverges in the static area, forming the characteristics of upward and downward reverse flow velocity, which further affects the stability of droplet transition.

Key words: Cold Metal Transfer Plus Pulse, Arc Additive Manufacturing, Droplet Transfer, Flow Field, Numerical Simulation

CLC Number: