超音频脉冲电弧增材制造TiC/Al-Cu合金组织性能优化调控机制

Microstructure and Property Optimization Mechanisms of TiC/Al-Cu Alloys Prepared by Ultrasonic Frequency Pulsed Wire Arc Additive Manufacturing

摘要:

为解决电弧增材制造TiC颗粒增强Al-Cu合金增强体颗粒团聚与孔隙缺陷等问题，本研究提出并验证了一种基于超音频脉冲（ultrasonic frequency pulse，UFP）电弧调控的熔丝增材制造工艺方法。通过调制电弧热力特性，显著增强了熔池内的对流与紊流行为，改变了传统Marangoni驱动的单环流模式，形成更加均匀的双环流结构，实现了对熔池温度场和流场的精准控制。基于构建的计算流体力学模型揭示了TiC颗粒在UFP电弧作用下的迁移及其与基体混合的机理，直接实验观测与仿真结果具有很好的一致性。结果表明，相较于常规工艺，UFP电弧有助于显著细化晶粒，提高组织均匀性，改善TiC颗粒的分布状态，降低孔洞与夹杂等典型缺陷的数量，该研究可为高性能Al-Cu合金增材制造提供新路径。

Abstract:

To address the issues of TiC particle agglomeration and pore defects of TiC particle-reinforced Al-Cu alloys prepared by wire arc additive manufacturing (WAAM), this study proposed a novel ultrasonic-frequency pulse (UFP)-assisted WAAM process. By modulating arc thermal characteristics, this method enhanced convective and turbulent behaviors in the melt pool, transitioning from a conventional Marangoni-driven flow to a more uniform dual-vortex structure. A computational fluid dynamics model was developed to trace TiC particle motion and revealed their improved mixing mechanism with the matrix under UFP conditions. Simulation results were validated by real-time melt pool imaging. Results showed that compared to conventional VPTIG, the UFP-VPTIG technique can significantly refine grains and improve homogeneity. Dispersed TiC particles are more uniformly, and porosity and segregation defects are reduced. This study offers a promising route for manufacturing high-performance Al-Cu alloy components.