铝合金熔滴复合电弧增材组织转变数值模拟及试验研究

doi:10.3901/JME.2025.18.170

摘要/Abstract

摘要： 以电弧为热源的铝合金增材制造具有高效、低成本、材料利用率高等优势，但是存在凝固过程复杂、性能不稳定、难以实现主动控制的局限。针对铝合金熔滴复合电弧增材工艺，耦合宏观熔池热质输运模型与微观组织演化相场模型，进行沉积过程凝固组织转变跨尺度数值计算。考虑洛伦兹力、表面张力以及电弧压力等因素计算沉积过程熔滴与电弧对熔池影响行为，分析了温度场分布演化规律。将熔池凝固参数代入相场模型计算熔池不同位置组织生长演化过程，结果表明，在熔池底部凝固组织呈现柱状晶结构，到熔池中上部逐渐满足液相形核条件，发生组织转变，从柱状晶转变为等轴晶。同时元素分布呈现明显显微偏析，在晶界处溶质浓度高，枝晶内部浓度较低。最后为了验证数值模拟的正确性，进行了样件金相与力学性能测试，电镜下观测结果和能谱分析结果与数值模拟表现出较高一致性；同时微小拉伸试验表明，熔池中上部材料的抗拉强度和伸长率均高于熔池底部材料。

关键词: 增材制造, 熔滴复合电弧沉积, 组织演变, 力学性能, 铝合金

Abstract: The additive manufacturing of aluminium alloy with arc as the heat source has the advantages of high efficiency, low cost and high material utilization, but it has the limitations of complex solidification process, unstable performance and difficulty in realizing active control. A macroscopic heat and mass transfer model coupled with a microscopic phase field model is used to calculate the solidification microstructure transition during the droplet hybrid arc additive manufacturing process for aluminum alloy. The Lorentz force, surface tension and arc pressure are considered in the model. The effects of droplets and arc on the molten pool during the deposition process are calculated, and the evolution of temperature field distribution is revealed. The results show that the microstructure at the bottom of the molten pool presents a columnar-grain structure, and gradually the nucleation conditions are satisfied in the liquid phase in the middle and upper part of the molten pool. The microstructure transformation from columnar to equiaxed grains occurs. In addition, the micro-segregation can be obviously observed. The concentration of solute elements is very high in the grain boundary zone, and the concentration in dendrite is low. Finally, in order to verify the numerical simulations, the metallographic and mechanical properties of the samples are tested. The metallographic observations and energy dispersive spectrometer (EDS) analysis results are in high agreement with the numerical simulations. The micro-tensile tests show that the tensile strength and elongation of the upper material in the deposition layer are higher than those of the bottom material in the melt pool.

Key words: additive manufacturing, droplet hybrid arc deposition, microstructure evolution, mechanical properties, aluminum alloy

中图分类号:

TH16

耿汝伟, 朱聪聪, 魏正英, 麻宁绪. 铝合金熔滴复合电弧增材组织转变数值模拟及试验研究[J]. 机械工程学报, 2025, 61(18): 170-180.

GENG Ruwei, ZHU Congcong, WEI Zhengying, MA Ninshu. Numerical Simulation and Experimental Study of Microstructure Transformation of Droplet Hybrid Arc Additive Manufacturing for Aluminum Alloy[J]. Journal of Mechanical Engineering, 2025, 61(18): 170-180.

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