205C/7075铝合金激光同轴熔丝增材制造组织与气孔耦合演化机理

doi:10.3901/JME.260077

摘要/Abstract

摘要： 激光同轴熔丝增材制造技术凭借其高成形柔性和材料熔化均匀等优势，为基于2系和7系铝合金的高性能异质材料整体结构的高效成形提供了新型有效解决方案。针对铝合金激光同轴熔丝增材制造过程中存在的冶金气孔缺陷问题，本研究采用实验分析与数值模拟结合的方法，分析了不同类型晶粒及晶粒不同位置处气孔分布的差异化特征，揭示了气孔析出初始特征与晶粒形核条件对组织与气孔竞协演化行为的影响机理。结果表明：205C铝合金过渡层C1等轴晶界气孔率(0.03%)显著高于晶内区域(0.01%)，7075铝合金过渡层C2柱状晶区气孔率(1.01%)与平均气孔直径(48.07 μm)分别为等轴晶区的10.1倍和1.68倍。凝固末期，柱状晶上部液相通道的气孔与下方气孔合并形成双晶界气孔，远离一次枝晶尖端的气孔被两侧柱状晶包裹形成三晶界交互气孔。多等轴晶间气孔受晶界均匀约束作用影响呈近球形形貌，柱状晶间气孔形貌受晶体取向约束呈沿晶界定向延伸的条状分布。随着柱状晶生长模式由汇聚型向平行型直至发散型转变，晶间气孔的长度、宽度和圆度逐渐增大。

关键词: 铝合金, 激光同轴熔丝增材, 微观组织, 气孔, 耦合演化

Abstract: Laser coaxial wire additive manufacturing, with its advantages of high forming flexibility and uniform material melting, offers a novel and effective solution for the efficient forming of high-performance heterogeneous material integral structures based on 2xxx and 7xxx series aluminum alloys. To address the metallurgical porosity problem during laser coaxial wire additive manufacturing of aluminum alloys, this study combines experimental analysis with numerical simulation to investigate the differential pore distribution characteristics across different grain types and locations. It further elucidates the influence mechanisms of initial pore precipitation features and grain nucleation conditions on the competitive and cooperative evolution of microstructure and porosity. The results demonstrate that in the 205C aluminum alloy transition layer C1, the porosity at equiaxed grain boundaries (0.03%) is significantly higher than that within grains (0.01%). In the 7075 aluminum alloy transition layer C2, the porosity (1.01%) and average pore diameter (48.07 μm) in the columnar grain zone are 10.1 times and 1.68 times those in the equiaxed grain zone, respectively. During the final solidification stage, pores in the upper liquid channels of columnar grains merge with underlying pores, forming double-grain-boundary pores, while pores distant from primary dendrite tips become encapsulated by adjacent columnar grains, resulting in triple-grain-boundary interactive pores. Pores between multiple equiaxed grains exhibit near-spherical morphology due to uniform grain boundary constraints, whereas those between columnar grains adopt an elongated, intergranular distribution due to crystallographic orientation constraints. As the columnar grain growth mode transitions from convergent to parallel and finally divergent, the length, width, and roundness of intergranular pores progressively increase.

Key words: aluminum alloy, laser coaxial wire additive manufacturing, microstructure, pore, coupling evolution

中图分类号:

TG156

占小红, 高转妮, 张凯昱, 王建峰, 李响, 徐方达. 205C/7075铝合金激光同轴熔丝增材制造组织与气孔耦合演化机理[J]. 机械工程学报, 2026, 62(3): 160-175.

ZHAN Xiaohong, GAO Zhuanni, ZHANG Kaiyu, WANG Jianfeng, LI Xiang, XU Fangda. The Coupling Evolution Mechanism of Microstructure and Pores during Laser Coaxial Wire Additive Manufacturing of 205C/7075 Aluminum Alloy[J]. Journal of Mechanical Engineering, 2026, 62(3): 160-175.

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