基于旁路电弧分流的GMA增材制造能量调控机理与组织演变规律研究

Gas metal arc-additive manufacturing（GMA-AM）has the advantages of low production cost and high deposition efficiency. However, heat accumulation in forming process is the technical bottleneck restricting the development of this technology. The project will use the bypass arc shunting method to control the energy of the GMA-AM process. The core idea is to redistribute the GMA-AM arc energy by adding the bypass arc. It can reduce the melting of the forming parts and decrease heat input when the wire melting speed is constant. In this case, bypass arc can relieve the heat accumulation, improve the microstructure and properties of GMA-AM fabricated parts. Finally, high efficiency and low heat input GMA-AM process can be realized. The main research contents include:（1）Mechanism of energy regulation in GMA-AM with bypass arc;（2）Thermal behavior of multiple deposition in GMA-AM with bypass arc;（3）Microstructure evolution and properties control in GMA-AM with bypass arc. The research of this project provides a new way to optimize and control GMA-AM process, reveals heat and mass transfer mechanism of GMA-AM with bypass arc, enriches the connotation of research of additive manufacturing. It is significant for achieving high deposition efficiency in GMA-AM process with low heat input.

熔化极电弧增材制造（GMA-AM）具有生成成本低、熔敷效率高等优势，然而成形过程热积累问题是限制该技术发展的技术瓶颈。本项目拟采用旁路分流的方法对GMA-AM过程进行能量调控，其核心思想是通过外加旁路电弧的作用使GMA-AM电弧能量重新分配，在丝材熔化速度不变的情况下减少成形件金属的熔化，降低成形热输入，缓解成形过程热积累，改善熔敷层组织，优化GMA-AM成形件性能，最终实现高效低热输入的增材制造过程。研究内容主要包括：（1）旁路电弧分流作用下GMA-AM能量调控机理；（2）旁路电弧分流作用下多重加热GMA-AM热行为研究；（3）旁路电弧分流作用下GMA-AM组织性能控制。本项目的研究为GMA-AM成形过程优化与控制提供了一种新的思路，揭示了旁路电弧下GMA-AM传热传质机制，丰富了增材制造研究内涵，对实现高熔敷效率、低热输入的GMA-AM过程有重要意义。

熔化极电弧增材制造(Gas Metal Arc-Additive Manufacturing，GMA-AM)以生产成本低、熔敷效率高等优点而受到关注。但是，过程中的热积累问题削弱了该工艺本身的优势。基于此本课题提出对GMA-AM过程的能量调控，通过引入旁路电弧，在不改变熔敷效率的前提下减少GMA-AM成形件的热输入，阐明旁路电弧能量调控机理，在此基础上研究旁路电弧作用下多重加热GMA-AM成形热行为，定量分析成形件热积累，以低合金高强钢材料为研究对象，揭示旁路电弧多重加热GMA-AM熔敷层金属组织演变规律，实现对熔敷层组织的调控，在相同条件下，旁路GMA-AM的热循环峰值温度和冷却时间较常规GMA-AM有所降低，影响了增材金属的组织和性能。在GMA-AM中引入旁路电弧，产生了更多的马氏体组织，提高了熔覆金属的硬度。旁路电弧对薄壁件的抗拉强度和屈服强度均有提高。旁路GMA-AM增材高强钢样件的平均抗拉强度为855 MPa，延伸率为19.5%。本项目研究成果对实现高效低热输入的GMA-AM具有较高的科学意义。